A patent is valid for 20 years from the date of application.
The patent must be renewed annually from the expiration
of the second year from the date of grant paying a fee
( refer to the regulations).
What is not patented: Such things as
(i) discoveries, scientific theories and mathematical
methods; (ii) plants, animals micro organisms other than
transgenic micro organisms and an essentially biological
process for the production of plants and animals other
than non biological and micro-biological processes;
(iii) schemes, rules or methods for doing business,
performing purely mental acts or playing games (iv) methods for treatment
of human or animal body by surgery or therapy and diagnostic
methods practiced on human or animal body (v) inventions
which are necessary to protect public order, morality
including human animal or plant life, health, or to avoid
serious prejudice to environment.