A summary of what Chapter VI of the Indian Patents Act has to say on the subject of Anticipation:

Anticipation by previous publication
An invention claimed in a complete specification is not deemed to have been anticipated merely because  the invention was published before an application for it to be granted patent protection was filed if the patentee or the applicant for the patent or any person from whom he derives title proves that the matter published was obtained from and then published without his consent. Additionally, he must prove that the application was made as soon as reasonably practicable  after he  learned of the publication. This does not apply if the invention was commercially worked in India before the filing of the patent application, otherwise than for the purpose of reasonable trial,  by him or with his consent.
If  a complete specification is filed in pursuance of an application for a patent made by a person being the true and first inventor or deriving title from him, an invention claimed in that specification is not deemed to have been anticipated only because another application for a patent in respect of the same invention  was made in contravention of the rights of that person, or because  the invention was used or published without the consent of the true and first inventor after the date of filing of that other application either by its applicant  or by any other person in consequence of any disclosure of any invention by that applicant

Anticipation by previous communication to Government
An invention claimed in a complete specification  is not deemed to have been anticipated  only because of the communication of the invention to the Government or to any person authorised by the Government to investigate the invention or its merits, or of anything done, in consequence of such a communication, for the purpose of the investigation.

Anticipation by public display, etc.
An invention claimed in a complete specification  is not deemed to have been anticipated  only because of:
a.    its display or use  with the consent of the true and first inventor or a person deriving title from him at an industrial or other exhibition notified by the Central Government  in the Official Gazette; or
b.    the publication of any description of the invention in consequence of the display or use of the invention at any such exhibition; or
c.    the use of the invention, after it has been displayed or used at any such exhibition and during the period of the exhibition, by any person without the consent of the true and first inventor or a person deriving title from him; or
d.    the description of the invention in a paper read by the true and first inventor before a learned society or published with his consent in the transactions of such a society,
if the application for the patent is made by the true and first inventor or a person deriving title from him not later than six months after the opening of the exhibition or the reading or publication of the paper, as the case may be.

Anticipation by public working
An invention claimed in a complete specification  is not deemed to have been anticipated only because it was publicly worked in India (by the patentee or applicant for the patent or any person from whom he derives title, or by any other person with the consent of the patentee or applicant for the patent or any person from whom he derives title) at any time within one year before the priority date of the relevant claim of the specification if the working was effected for the purpose of reasonable trial only and if it was reasonably necessary, having regard to the nature of the invention, that the working for that purpose should be effected in public.
 
Anticipation by use and publication after provisional specification
If  a complete specification is filed or proceeded with in pursuance of an application which was accompanied by a provisional specification or is treated as such by virtue of a direction under Section 9(3) if the Patents Act, 1970,   the Controller will not refuse to grant the patent, and the patent  is not revoked or invalidated, only because any matter described in the provisional specification or in the specification treated as  such was used in India or published in India or elsewhere at any time after  that specification was filed.
If  a complete specification is filed in pursuance of a convention application,  the Controller will not refuse to grant the patent, and the patent  is not revoked or invalidated, only because any matter disclosed in any application for protection in a convention country upon which the convention application is founded was used in India or published in India or elsewhere at any time after the date of that application for protection.