A Patent is a monopoly right granted to person who has invented a new and useful article or an improvement of an existing article or a new process of making an article.

Inventions patentable :-

Art, process, method or manner of manufacture;
Machine, apparatus or other article;
Substance produced by manufacture.

Inventions not patentable :-

Frivolous or obvious inventions.
Inventions which would be contrary to law or morality or injurious to public health.
Mere discovery of scientific principle.
Mere discovery of an abstract theory.
Mere discovery of any new property or new use for a known substance or process or apparatus -- unless results to new products or employs one new reactant.
Mere admixtures.
Mere arrangement / rearrangement of known devices functioning independently.
Method or process of testing applicable during the process of manufacture for rendering the machine or other equipment more efficient for improvement / restoration of the existing machine or for the improvement of manufacture.
Method of agriculture or horticulture.
Any process for the medicinal or other treatment of human beings or any process for a similar treatments of any animals or plants to render them free of disease or to increase their economic value or that of their products.
Inventions relating to atomic energy

Section 5 :-

Inventions where only methods or processes of manufacture are patentable :

1 In the case of inventions -

(a) Claiming substances intended for use, or capable of being used, as food or as medicine or drug, or

(b) Relating to substances prepared or produced by chemical processes ( including alloys, optical glass, semi-conductors and inter-metallic compounds ),
No patent shall be granted in respect of claims for the substances themselves, but claims for the methods or processes of manufacture shall be patentable.

2 Notwithstanding anything contained in sub-section (1), a claim for patent of an invention for a substance itself intended for use, or capable of being used, as medicine or drug, except the medicine or drug specified under sub-clause (v) of clause (1) of sub-section (1) of section 2, may be made and shall be dealt, without prejudice to the other provisions of this act, in the manner provided in chapter IV -a i.e., the controller shall not refer the application to an examiner for making a report till the 31st day of december, 2004.

Requirements for filing the patent in india :-

Full name, address & nationality of applicant (s) and inventor (s).
Specification , provisional / complete drawings , claims and abstract.
List of countries to claim priority , if any, where the application / applications for the grant of patent has / have been filed , alongwith date and application number.
Power of attorney

Procedure for the grant of patent:-

The application is examined by patent office and objections, if any, are raised thereto.
The specification is advertised after the objections, if any, are removed to the satisfaction of the patent office.
The patent is sealed if there is no opposition by the third party within a period of 4 months of advertisement.
After sealing of the patent the certificate is issued by the patent office.
Renewal:-
The patent is renewed every year from the date of patent.

Term of patents:- 20 years