In Subhash Kashinath Mahajan v/s State Of Maharashtra, (March 2018), the sc observed that the provisions of The Scheduled Castes and The Scheduled Tribes (Prevention Of Atrocities) Act, 1989 (SC/ST act) which provided punishment for atrocities against people belonging to SCs and STs were getting misused by them against the general people( for ex. Putting false allegations/charged). So the SC laid down the following conditions to be fulfilled before instituting any case under this act in order to relax its stringent effect.

The SC held:
83. Our conclusions are as follows:

1. Proceedings in the present case are clear abuse of process of court and are quashed.
2. There is no absolute bar against grant of anticipatory bail in cases under the Atrocities Act if no prima facie case is made out or where on judicial scrutiny the complaint is found to be prima facie mala fide. We approve the view taken and approach of the Gujarat High Court in Pankaj D Suthar (supra) and Dr. N.T.Desai (supra) and clarify the judgments of this Court in Balothia (supra) and Manju Devi (supra);
3. In view of acknowledged abuse of law of arrest in cases under the Atrocities Act, arrest of a public servant can only be after approval of the appointing authority and of a nonpublic servant after approval by the S.S.P. which may be granted in appropriate cases if considered necessary for reasons recorded. Such reasons must be scrutinized by the Magistrate for permitting further detention.
4. To avoid false implication of an innocent, a preliminary enquiry may be conducted by the DSP concerned to find out whether the allegations make out a case under the Atrocities Act and that the allegations are not frivolous or motivated.
5. Any violation of direction (iii) and (iv) will be actionable by way of disciplinary action as well as contempt.

The above directions are prospective.
But as a result of this judgment multiple protests and demonstrations ensued across the entire country with a sense of displeasure and discontentment over the judgment.

So, in order to undo the ratio of this judgment, the Parliament brought an amendment in this act which practically reversed this judgment.

The Parliament introduced sec. 18A in the The Scheduled Castes And The Scheduled Tribes (Prevention Of Atrocities) Amendment Act, 2018

18A.

1. For the purposes of this Act:
   1. preliminary enquiry shall not be required for registration of a First Information Report against any person; or
   2. the investigating officer shall not require approval for the arrest, if necessary, of any person,against whom an accusation of having committed an offence under this Act has been made and no procedure other than that provided under this Act or the Code shall apply.
2. The provisions of section 438 of the Code shall not apply to a case under this Act, notwithstanding any judgment or order or direction of any Court.

The condemnation was so severe that the Parliament did not wait for the SC to hear the review petition over this Subhash Kashinath judgment and amended it to include section 18A.

So, this judgment of UOI v State of Maharashtra is the review judgment of Subhash Kashinath Mahajan wherein the SC partly withdrew the directions issued in Subhash Kashinath Mahajan case. (Direction no. (iii) and (iv).

Whereas the judgment of Prithvi Raj Chauhan v UOI (2020) is the judgment wherein the SC formally upheld the constitutionality of the amendment of SC/ST act of 2018. (Sec.18A)
(Here, in UOI v State of Maharashtra, the issue was review of the Subhash Kashinath Mahajan case and withdrawal of its directions).

Although The Practcal Effect Of Both The Judgments Is Same Because 2018 Amendment Was Nothing But An Effort To Reverse The Directions Of Subhash Kashinath Mahajan Case And The Uoi v/s State Of Maharahstra Also Did The Same Thing I.E. Partly Withdrew The Directions Of Subahsh Kashnath Mahajan Case.

Judgment Of Uoi v/s State Of Maharashtra: October, 2019 (Review judgment of Shubhash Kashinath Mahajan case)

The SC delivered its judgment relying upon two premises:

1. SC cannot breach the solemn doctrine of "separation of powers".
   {Thus, the SC issuing directions in Subhash Kashinath Mahajan are extra Statutory and thus breach of separation of power

Excerpts From The Judgment:

1. (Statement of Objects and Reasons of the act)
   "Despite various measures to improve the socio-economic conditions of the Scheduled Castes and the Scheduled Tribes,they remain vulnerable. They are denied number of civil rights.They are subjected to various offences, indignities, humiliations, and harassment. They have, in several brutal incidents, been deprived of their life and property. Serious crimes are committed against them for various historical, social, and economic reasons...
   
   When they assert their rights and resist practices of untouchability against them or demand statutory minimum wages or refuse to do any bonded and forced labour, the vested interests try to cow them down and terrorize them.3When the Scheduled Castes and the Scheduled Tribes try to preserve their selfrespect or honour of their women, they become irritants for the dominant and the mighty.
   
   Occupation and cultivation of even the Government allotted land by the Scheduled Castes and Scheduled Tribes is resented and more often these people become victims of attacks by the vested interests. Of late, there has been an increase in the disturbing trend of the commission of certain atrocities like making the Scheduled Caste persons ear inedible substances, like human excreta and attacks on and mass killings of helpless Scheduled Castes and the Scheduled Tribes and rape of women belonging to the Scheduled Castes and the Scheduled Tribes. Under the circumstances, the existing laws like the Protection of Civil Rights Act, 1955 and the normal provisions of the Indian Penal Code have been found to be inadequate to check these crimes.
   
   Thus, A special legislation to check and deter crimes against them committed by nonScheduled Castes and nonScheduled Tribes has, therefore, become necessary."
    
2. (SC referred to various case laws and famous quotes of learned philosophers and jurists to justify the separation of powers doctrine)
   
   Mr. Justice Stone of the Supreme Court of the United States has delineated these limitations in United States v. Butler: 80L Ed477: 297 US 1 (1936) thus: (L.Ed p. 495)
   
   "The power of Courts to declare a statute unconstitutional is subject to two guiding principles of decision which ought never to be absent from judicial consciousness. One is that Courts are concerned only with the power to enact statutes, not with their wisdom.The other is that while unconstitutional exercise of power by the executive and legislative branches of the Government is subject to judicial restraint, the only check upon our exercise of power is our own sense of selfrestraint. For the removal of unwise laws from the statute books appeal lies not to the Courts but to the ballot and to the processes of democratic Government."
   
   Frankfurter, J. of the U.S. Supreme Court dissenting in the controversial expatriation case of Trop v. Dulles, 356 US 96observed as under:
   
   "All power is, in Madison's phrase, "of an encroaching nature." Judicial power is not immune against this human weakness. It also must be on guard against encroaching beyond its proper bounds, and not the less so since the only restraint upon it is selfrestraint.."
   
   In Bhim Singh v. Union of India, (2010) 5 SCC 538, it was held asunder,
   
   "Thus, the test for the violation of separation of powers must be precisely this. A law would be violative of separation of powers not if it results in some overlap of functions of different branches of the State, but if it takes over an essential function of the other branch leading to lapse in constitutional accountability. It is through this test that we must analyse the present Scheme."
    
3. (SC observed the present sorrow state of affairs of the SCs and STs)
   As to prevailing conditions in various areas of the country, we are compelled to observe that SCs/STs are still making the struggle for equality and for exercising civil rights in various areas of the country.The members of the Scheduled Castes and Scheduled Tribes are still discriminated against in various parts of the country. In spite of reservation, the fruits of development have not reached to them, by and large, they remain unequal and vulnerable section of the society.
   
   The classes of Scheduled Castes and Scheduled Tribes have been suffering ignominy and abuse, and they have been outcast socially for the centuries. The efforts for their upliftment should have been percolated down to eradicate their sufferings. Though, Article 17 of the Constitution prohibits untouchability, whether untouchability has vanished? We have to find the answer to all these pertinent questions in the present prevailing social scenario in different parts of the country. The clear answer is that untouchability though intended to be abolished, has not vanished in the last 70 years.
   
   We are still experimenting with 'tryst with destiny. 'The plight of untouchables is that they are still denied various civil rights; the condition is worse in the villages, remote areas where fruits of development have not percolated down. They cannot enjoy equal civil rights. So far, we have not been able to provide the modern methods of scavenging to Harijans due to lack of resources and proper planning and apathy. Whether he can shake hand with a person of higher class on equal footing?
   
   Whether we have been able to reach that level of psyche and human dignity and able to remove discrimination based upon caste? Whether false guise of cleanliness can rescue the situation, how such condition prevails and have not vanished, are we not responsible? The answer can only be found by soul searching.
   
   However, one thing is sure that we have not been able to eradicate untouchability in a real sense as envisaged and we have not been able to provide downtrodden class the fundamental civil rights and amenities, frugal comforts of life which make life worth living. More so, for Tribals who are at some places still kept in isolation as we have not been able to provide them even basic amenities, education and frugal comforts of life in spite of spending a considerable amount for the protection, how long this would continue.
   
   Whether they have to remain in the status quo and to entertain civilized society? Whether under the guise of protection of the culture,they are deprived of fruits of development, and they face a violation of traditional rights?
    
4. (Ratio decidendi)
   
   1. On the argument that SC/ST people misuse the stringent provisions of the SC/ST act and falsely accuse general people of committing atrocities against them:-
      
      There is no presumption that the members of the Scheduled Castes and Scheduled Tribes may misuse the provisions of law as a class and it is not resorted to by the members of the upper Castes or the members of the elite class. For lodging a false report, it cannot be said that the caste of a person is the cause. It is due to the human failing and not due to the caste factor. Caste is not attributable to such an act.
      
      On the other hand, members of the Scheduled Castes and Scheduled Tribes due to backwardness hardly muster the courage to lodge even a first information report, much less, a false one. In case it is found to be false/unsubstantiated, it may be due to the faulty investigation or for other various reasons including human failings irrespective of caste factor. There may be certain cases which may be false that can be a ground for interference by the Court, but the law cannot be changed due to such misuse. In such a situation, it can betaken care in proceeding under section 482 of the Cr.PC.
      
      As a matter of fact, members of the Scheduled Castes and Scheduled Tribes have suffered for long, hence, if we cannot provide them protective discrimination beneficial to them, we cannot place them at all at a disadvantageous position that may be causing injury to them by widening inequality and against the very spirit of our Constitution. It would be against the basic human dignity to treat all of them as a liar or as a crook person and cannot look at every complaint by such complainant with a doubt.
      
      Eyewitnesses do not come up to speak in their favour. They hardly muster the courage to speak against upper caste, that is why provisions have been made byway of amendment for the protection of witnesses and rehabilitation of victims.
      
      To treat such incumbents with a rider that a report lodged by an SCs/STs category, would be registered only after a preliminary investigation by Dy. S.P., whereas under Cr.PC a complaint lodged relating to cognizable offence has to be registered forthwith. It would mean a report by uppercaste has to be registered immediately and arrest can be made forthwith, whereas, in case of an offence under the Act of 1989, it would be conditioned one.
      
      It would be opposed to the protective discrimination meted out to the members of the Scheduled Castes and Scheduled Tribes as envisaged under the Constitution in Articles 15, 17 and 21 and would tantamount to treating them as unequal, somewhat supportive action as per the mandate of Constitution is required to make them equals. It does not prima facie appear permissible to look them down in any manner. It would also be contrary to the procedure prescribed under the Cr.PC and contrary to the law laid down by this Court in Lalita Kumari (supra)
       
   2. Regarding Direction no. (iii):
      Permission of the appointing authority to arrest a public servant is not at all statutorily envisaged( neither in CrPC or in any other law). It is encroaching on a field which is reserved for the legislature. The direction amounts to a mandate having legislative colour which is a field not earmarked for the Courts. (Thus, Breach Of Separation Of Powers Doctrine).
      
      The direction is discriminatory and would cause several legal complications. Approaching appointing authority for approval of arrest of a public servant in every case under the Act of 1989 is likely to consume sufficient time. The appointing authority is not supposed to know the ground realities of the offence that has been committed, and arrest sometimes becomes necessary forthwith to ensure further progress of the investigation itself. Often the investigation cannot be completed without the arrest.
      
      There may not be any material before the appointing authority for deciding the question of approval. To decide whether a public servant should be arrested or not is not a function of appointing authority, it is wholly extrastatutory. In case appointing authority holds that a public servant is not to be arrested and declines approval, what would happen, as there is no provision for grant of anticipatory bail. It would tantamount to take away functions of Court. To decide whether an accused is entitled to bail under Section 438 in case no prima facie case is made out or under Section 439 is the function of the Court.
      
      The direction of appointing authority not to arrest may create conflict with the provisions of Act of 1989 and is without statutory basis. Assuming it is permissible to obtain the permission of appointing authority to arrest accused, would be further worsening the position of the members of the Scheduled Castes and Scheduled Tribes. If they are not to be given special protection, they are not to be further put in a disadvantageous position. The implementation of the condition may discourage and desist them even to approach the Police and would cast a shadow of doubt on all members of the Scheduled Castes and Scheduled Tribes which cannot be said to be constitutionally envisaged.
      
      Inter alia for the reasons as mentioned earlier, we are of the considered opinion that requiring the approval of SSP before an arrest is not warranted in such a case as that would be discriminatory and against the protective discrimination envisaged under the Act. Apart from that, no such guidelines can prevail, which are legislative. When there is no provision for anticipatory bail, obviously arrest has to be made.
      
      Without doubting bona fides of any officer, it cannot be left at the sweet discretion of the incumbent howsoever high. The approval would mean that it can also be ordered that the person is not to be arrested then how the investigation can be completed when the arrest of an incumbent, is necessary, is not understandable. For an arrest of accused such a condition of approval of SSP could not have been made a sine qua non, it may delay the matter in the cases under the Act of 1989.
       
   3. Regarding direction no. (iv):
      The direction has also been issued that the Dy. S.P. should conduct a preliminary inquiry to find out whether allegations make out a case under the Atrocities Act, and that the allegations are not frivolous or motivated. In case a cognizable offence is made out, the FIR has to be out rightly registered, and no preliminary inquiry has to be made as held in Lalita Kumari (supra) by a Constitution Bench.
      
      There is no such provision in the Code of Criminal Procedure for preliminary inquiry or under the SC/ST Act, as such direction is impermissible. Moreover, it is ordered to be conducted by the person of the rank of Dy. S.P. The number of Dy. S.P. as per stand of Union of India required for such an exercise of preliminary inquiry is not available. The direction would mean that even if a complaint made out a cognizable offence, an FIR would not be registered until the preliminary inquiry is held. In case a preliminary inquiry concludes that allegations are false or motivated, FIR is not to be registered in such a case how a final report has to be filed in the Court.
      
      The direction (iv) cannot survive for the other reasons as it puts the members of the Scheduled Castes and Scheduled Tribes in a disadvantageous position in the matter of procedure vis a vis to the complaints lodged by members of upper caste, for later no such preliminary investigation is necessary, in that view of matter it should not be necessary to hold preliminary inquiry for registering an offence under the Atrocities Act of 1989.
      THUS THE SC RECALLED (withdrew) DIRECTIONS NO. (III) AND (IV).
       
   4. Regarding direction no. (ii):
      The SC still upheld Direction no. (ii). The SC by relying on the ratio of State of MP v Ram Krishna Balothia, upheld the constitutionality of sec. 18 of the act and held that there is no absolute bar against grant of anticipatory bail in cases under the Atrocities Act if no prima facie case is made out or where on judicial scrutiny the complaint is found to be prima facie mala fide.

Important Provisions Of The Sc/St Act:
Sec. 2,3,4,5,7,8,10,14,15,15A, 18,18A,19.