The decision was taken at a Cabinet meeting here presided over by Prime Minister Narendra Modi.
"Today the Cabinet decided to ratify the Paris Agreement," Human Resource Development Minister Prakash Javadekar later told reporters.
Modi had announced during the BJP National Council meeting on Sunday that India would ratify the 21st Conference of Parties (CoP) protocol on combating climate change on the occasion of Mahatma Gandhi's birth anniversary on October 2.
Javadekar said 61 countries had ratified the protocol, but implementation of the agreement also required that at least 55 per cent of world emissions were captured among the countries ratifying it.
He said there was a shortfall of 3.5 per cent to cross the "55 per cent pollution barrier" and it would be crossed with India's decision to ratify the agreement.
"India became a decisive partner in the ratification process," he said.
Javadekar said the Paris agreement would get implemented post-2020 and India would seek action from the developed world in the pre-2020 period.
"India's decision to ratify the agreement will take the number of cumulative level of emission of countries that have ratified the agreement so far to 51.89 per cent," said an official statement.
"With the willingness expressed by several other countries to ratify the agreement before the end of this year, it is expected that the Agreement will enter into force soon and give a thrust to the global actions to address climate change," it added.
The statement further said: "While agreeing to ratify the Paris Agreement, the Cabinet has also decided that India should declare that it will treat its national laws, its development agenda, availability of means of implementation, its assessment of global commitment to combating climate change, and predictable and affordable access to cleaner source of energy as the context, in which the Agreement is being ratified."
The Paris Agreement was adopted by 185 nations on December 12 last year and India signed it in New York on April 22 this year. A total of 191 countries have signed the Paris Agreement so far.
As per the provisions of the Paris Agreement, the treaty will come into force as and when 55 countries contributing to 55 per cent of the total global emissions ratify the Agreement.
So far, 61 countries have deposited their instruments of ratification, acceptance or approval, accounting for 47.79 per cent of the total global greenhouse gas emissions.
