India’s Patent Act mandates patent holders to pay renewal or maintenance fee for keeping their patents in force for the entire term.
Like most countries, patents in India are granted for a period of 20 years from the date of filing of the application, and international filing date in case of the Patent Cooperation Treaty (PCT) National phase application.
The first renewal fee is payable before the expiration of the second year of the patent – which is essentially the start of the third year of the patent.
Subsequently, the renewal fee is paid before the expiration of the previous year of the patent. For example, the renewal fee for the 7th year would be payable before the expiration of the 6th year of the patent.