India's ratification of Paris agreement could see it enacted before 2018
India has formally joined the Paris agreement, which is trying to tackle climate change by taking measures to ensure that the global temperature does not rise 2°C above pre-industrial levels.
The country is the second largest by population in the world behind China and is the third largest emitter of greenhouse gases.
Their formal engagement with the agreement takes the global pact a significant step closer to its enactment.
The deal, which was agreed by nearly 200 countries in Paris last December, aims to slash greenhouse gas emissions by shifting away from fossil fuels.
It needs to be formally ratified by countries representing at least 55 percent of global carbon dioxide emissions before taking effect. This target received a huge boost last week after it was ratified by EU ministers which could bring it into effect prior to the original target of 2020. The agreement could even be formally enacted ahead of the next round of climate talks in November, in Morocco.
"The Secretary-General calls on all Parties to accelerate their domestic procedures in order to join the agreement as soon as possible this year," said a spokesman for the UN Secretary-General in a statement.
The United States and China, the world's two biggest emitters, submitted their approvals to the United Nations last month.
Concerns about the participation of the United States loom over the deal but cementing the accord before the US presidential election on 8 November would make it harder to challenge if Republican Donald Trump, who has opposed it, beats Democrat Hillary Clinton, a strong supporter.
President Obama welcomed India's ratification in a tweet, saying Prime Minister Narendra Modi and the country was carrying on the legacy of Mahatma Gandhi and his belief "in a world worthy of our children."
India had called for more work on the agreement ahead of its ratification on Sunday, with its environment ministry saying the Paris agreement laid a "broad framework" but detailed guidelines and rules were needed for it to become operational.
The ministry also criticised developed countries, saying their populations "live extravagant lifestyles with a high carbon footprint".
It said it was "very crucial" to advance key issues, including those related to finance and technology transfer, at the meeting in Marrakech next month, where India also plans to urge developed countries to do more.
"At Morocco India will insist on a concrete roadmap from developed countries," the ministry said.
The urgency of reducing the impact of climate change was made clear in August after the latest State Of The Climate report showed that dozens of climate records were broken in 2015.