– In the hilly Singrauli region of northern India, the critically polluted landscape was once forest and fields of grain. But after four decades of industrial development, this is India's power hub. More than a dozen coal mines and power plants spread over two states generate a fifth of the country's electric power. The region is a key driver of India's greenhouse-gas emissions, the third-highest in the world.

Coal production is slated to expand here in the coming months, part of the new government's ambitious push to double India's output to more than 1 billion tons annually to meet the needs of a burgeoning economy — with growth now set to outpace China's.

With President Obama in India for talks with Prime Minister Narendra Modi, U.S. officials had hoped to announce a deal on climate change that would be a modest complement to the historic deal the U.S. reached with China.

But little progress has been made. India's energy deficit is staggering. An estimated 300 million people live without power. The national power grid was completed just last year.

On Sunday, Obama and Modi announced a deal to clear the way for U.S. companies to help build nuclear power plants in India, potentially bringing tens of billions of dollars and thousands of jobs to the U.S. But even so, proposed reactors would take many years to complete.

Coal, by contrast, is plentiful. India has the world's fifth-largest reserves. "The question is, what do you have in hand? We have coal," said coal secretary Anil Swarup. "There isn't much choice available."

Despite international pressure, India's climate negotiators have been reluctant to commit to specific emissions targets in part because the country must depend on coal as its primary energy source for at least the next decade.

U.S. officials are seeking a significant plan from India that can be part of a global climate deal later this year. The challenge for Modi's government, officials say, is to juggle international environmental pressure with the pressing basic needs of round-the-clock electricity and toilet access for every home, key goals for Modi's fledgling government.