The 3-judge bench of Karnataka High Court held that Section 8A of Dowry Prohibition Act 1961 is constitutionally valid and the burden of proof laid on the accused in offences under this Act carry onus on the Prosecution to discharge their duty to establish their case based on foundational facts relevant and only then the proof of burden shifts to accused.

From Paras 4-8,

4. It is true that if Section 8-A of the Act, is read literally, an impression is gathered therefrom that once an accused is prosecuted and charged for the offences under Sections 3 and 4 of the Act, then the entire burden is on him to show that he had not committed any offence and the prosecution may not be required to prove anything else except placing implicit reliance on the contents of the charge framed against the accused. But, on a closer scrutiny, such first-hand impression about the Section gets dispelled. It has to be kept in view that Section deals with burden of proving innocence in given cases. Therefore the Section,in substance, creates a Rule of Evidence and deals with casting of burden of proof in certain cases on the accused. A close reading of the Section shows that merely because the accused is charged with offences under Section 3 or Section 4 of the Act, the initial burden which is always on the prosecution to prove basic ingredients of the Sections for bringing home the charges to the accused will not get displaced or dispensed with. Section 8-A will have to be read with Section 2, which defines the term dowry. When so read, it becomes clear that when an accused is charged of an offence of giving or taking or abetting in giving or taking any dowry, under Section 3, the following ingredients of the offence will have to be established before a competent Criminal Court before which the accused is prosecuted.
i) any property or valuable security must be proved to have been given or taken by the accused pursuant to an agreement or otherwise; or
ii) the accused must be shown to have abetted such giving or taking of any property or valuable security;
iii) such giving or taking of any property or valuable security either directly or indirectly or its abetment must be done by any party to the marriage vis-a-vis the other party to the marriage; or;
iv) such giving or taking of any property or valuable security either directly or indirectly or its abetment is done by the parents of either party to a marriage or by any other person, for the benefit of either party to the marriage or any other person;
v) such property or valuable security is given or taken at or before or at any time after the marriage;
vi) such property or valuable security must be given in connection with the marriage of said parties.
5. Now it is obvious that before any offence can be brought home to the accused under Section 3 read with Section 2 of the Act, the aforesaid ingredients have to be established. So far as Section 8A is concerned, all that it mandates is that the burden of proof that he has not committed such an offence is on the accused. Meaning thereby, that it will be for the accused to show that he had not taken or given or abetted in giving or taking any property or valuable security in connection with the marriage of the said parties. He will have to show that last ingredient of the offence being ingredient No. (vi), is not established.The only burden cast on the accused is to prove that he had not committed offence of giving or taking or abetting the giving or taking of dowry as contemplated by Section 3 of the Act. It is not as if he has also to prove that he has not taken or given or abetted in giving or taking any property or valuable security or that he has not taken or given or abetted in giving or taking any property or valuable security or that he has to disprove all the ingredients (i) to (vi). As per Section 8A, once prosecution establishes beyond reasonable doubt the basic ingredients (i) to (v), burden shifts on the accused to prove that the last one is not established viz., that he had not taken or given or abetted in giving or taking any property or valuable security in connection with the marriage of the said parties. The Section, of necessity, will have to be read down as aforesaid.
6. Similarly, for the purpose of proving an offence under Section 4, Section 8A will have to be read with Sections 4 and 2 of the Act. On a conjoint reading of these provisions, it becomes clear that before any offence under Section 4 is brought home to an accused, the following facts will have to be established:
(1) The accused must be shown to have demanded directly or indirectly from the parents or other relatives or guardian of a bride or bridegroom, as the case may be;
(2) Any property or valuable security to be given by one party to the marriage to the other party to the marriage; or
(3) Any property or valuable security to be given by parents of either party to the marriage or by any other person, to either party to the marriage or to any other person;
(4) Such demand should be made at or before or any time after the marriage;
(5) Such demand for any property or valuable security must be in connection with the marriage of the said parties.
Before any offence under Section 4 is brought home to the accused, all the aforesaid ingredients must be established. So far as the first four ingredients are concerned, they will have to be established as basic facts by the prosecution and only when the burden would shift to the accused to show that he had not demanded directly or indirectly any property or valuable security in connection with the marriage of the said parties. The burden of proving non-existence of last ingredient rests on the accused as per Section8A of the Act. But the initial burden to establish beyond reasonable doubt the aforesaid ingredients (1) to (4) will rest on the prosecution. Once these basic ingredients are established by the prosecution, the burden would shift on the accused to show that such demand if any by him was not in connection with the marriage of the said parties. Meaning thereby, that he had not demanded any dowry from the parents or other relatives or guardian of a bride or bridegroom, as the case may be. Thus burden will shift on him only to establish that the last ingredient is not proved. Section 8-A, in its operation, will have to be read down in the light of Sections 2, 3 and 4 of the Act. Once it is so read down, the challenge to the said Section on the anvil of Articles 14, 20(3) and 21 of the Constitution of India, would not survive. However, as the learned Advocate for the appellant has sought to challenge the Constitutional validity of Section 8-A on the anvil of Articles 14, 20(3) and 21 of the Constitution, we may now deal with these challenges.

From Para 9,

9. As we have discussed earlier, if Section 8-A is read down as aforesaid, then there would remain no substance in what the learned Advocate submits. Once it is read down as indicated hereinabove, then the challenge to this Section on the anvil of Article 14 of the Constitution of India, would not survive. The prosecution will have to lead in the first instance evidence to prove the basic ingredients of the offences under Sections 3 and 4. Once the prosecution proves them beyond reasonable doubt, then only the burden is shifted on the accused under Section 8A of the Act. Thus, the initial burden will rest on the prosecution to bring home the basic ingredients of the Sections and that will never shift on the accused under Section 8A of the Act. The Section so read down, would represent only a rule of evidence and nothing more. Even the objects and reasons for introducing Section 8-A to which we have made reference earlier, clearly indicate the legislative intent that the Section is to serve only as a rule of evidence by casting on the accused the burden of proving that he had not taken or given or abetted in taking or giving of dowry or that he had not demanded either directly or indirectly any dowry.

Citations: [1995 ALT CRI 1 25], [1993 ILR KAR 3035], [1994 DMC 1 356], [1995 CRIMES 1 573], [1994 KARLJ 3 335], [1994 KANTLJ 3 335], [1993 SCC ONLINE KAR 240], [1994 KANT LJ 3 335], [1993 HLR 2 672]

Other Source links:
https://indiankanoon.org/doc/1973279/
https://www.casemine.com/judgement/in/56093aeee4b0149711228334

What exactly is Section 8A of dowry prohibition act

Index of Dowry related Judgments is here.