From which of the following does the term of a patent start? I. Date of filing of Provisional…

Section 53(1) of the Patents Act, 1970 runs the term for twenty years "from the date of filing of the application", and section 45(1) dates the patent as of that date. Where a provisional specification is filed first, the application is filed on that date, not on the later filing of the complete specification. A convention application counts from its date of filing in India, not from the foreign priority date. A national phase application counts from the international filing date (section 138), not the date of entry into India.