India has agreed to work toward joining the Paris Agreement on climate change this year, giving momentum to the international fight to curb global warming.
President Barack Obama met with Indian Prime Minister Narendra Modi at the White House on Tuesday.
"We discussed how we can, as quickly as possible, bring the Paris Agreement into force," Obama told reporters during talks in the Oval Office.
Both countries participated in the talks that led to the historic climate pact in France.
The United States intends to ratify the agreement this year, and the two countries said in a joint statement that India would aim to do the same.
India is the world's third largest greenhouse gas emitter after China and the United States.
"India and the United States recognise the urgency of climate change and share the goal of enabling entry into force of the Paris Agreement as early as possible," the statement from the two countries said.
"The United States reaffirms its commitment to join the agreement as soon as possible this year. India similarly has begun its processes to work toward this shared objective."
The agreement, forged last year, will take effect when at least 55 countries representing 55 per cent of global emissions ratify it.
As of late last month 17 small countries had ratified the pact, according to the United Nations, and many others including the United States and China have pledged to ratify it in 2016.
Environmental groups had hoped Modi would say that India was ready to ratify the agreement during his Washington trip to cross that 55 per cent threshold.
Brian Deese, senior adviser to Obama, said the joint statement should inspire other countries to follow suit.
The two countries welcomed the start of work to build six Westinghouse AP 1000 reactors in India, the culmination of 10 years of working to resolve civil nuclear issues.
India and the US Export-Import Bank are working to complete a financing package for the project.
The Nuclear Power Corporation of India Ltd, and Westinghouse confirmed engineering and site design work will begin immediately and contractual arrangements will be completed by June 2017.
