As per Section 2(1)(j) and (ja) of the Indian Patents Act, an invention should be new, must have inventive step, i.e. advanced to the existing prior-art technology and last but not the least should have commercial application. An invention having the said features is considered to constitute an invention as per the prevailing Indian Patents Act.

When an invention successfully passes these three check points as stated in sections 2(1)(j) and (ja), then only an invention is called to be an invention under the Act.  Then this invention is further assessed for its patentability by section 3 of the Indian Patents Act.

Section 3 does not state what are patentable inventions. It actually excludes those inventions which are not patentable under the purview of the Act even though they are qualified for section 2(1)(j) and (ja). 

In view of the above fact, it can be assumed that any invention directed to a product or process, which satisfies section 2(1)(j) and (ja) and does not come to the exclusion as stated in section 3, are patentable in India.

Non patentable inventions within the meaning of the prevailing Act:

• Frivolous inventions or inventions which claim anything obviously contrary to the well established natural laws
• Commercial exploitation of which would be contrary to public order or morality; which causes prejudice to human, animal or plant or to the environment
• Mere formulation or discovery of a scientific principle; discovery of any naturally occurring living or non-living substance
• New form of a known substance e.g. salts, esters, ethers, polymorphs, metabolites, pure forms, particle sizes, isomers etc, which does not have enhanced efficacy; new property or use of a known substance or mere use of a known process, machine or apparatus;
• A substance obtained by mere admixture or a process of producing the same, unless the substance shows synergistic effect
• Mere arrangement, rearrangement or duplication of known devices
• A method of agriculture or horticulture
• Any process related to medicine, surgery, curative purpose, prophylaxis, diagnosis, therapy or other treatment of human beings or animals to render them free of disease or increase their economic value or that of their products. However, method for treatment of plants are considered to be patentable (w.e.f. 20-5-2003)
• Plants and animals in whole, or any part thereof; essentially biological process for production or propagation of plants and animals. However, Genetically modified micro-organisms are considered to be patentable   
• A mathematical or business method or a computer program per se or algorithms
• Invention related to Literary, dramatic, musical works or method performing mental act
• Presentation of information
• Topography of integrated circuits
• Invention, which, in effect, is traditional knowledge