Greentech Media

Of course, challenges remain. For one thing, clean-energy sources are too expensive today.

Pankaj Sehgal, director and head of technology and cleantech investments at the Sun Group, said many users of dirty energy, such as kerosene, are poor, making taxes on carbon politically unacceptable.

The environment still isn't a major priority in India because it is facing "more mundane, pressing issues," he said.

But India is the fifth-largest polluter today and will soon be the third, meaning it will face strong political pressure to go greener, he said.

And with a population of 1.1 billion consumers, far larger than that of the United States, it's potentially a "huge" and "very fertile" market, he said.

As clean technologies get cheaper, Khosla said he expects India to adopt them.

"I subscribe to a fairly radical view that fossil fuels are going to be more expensive than clean technologies and then the question of adoption goes away," he said. "The question of what to do with India and China are both very relevant and very solvable. The critical thing is to empower entrepreneurs to do what they have to do."

Hycrete, a startup that makes concrete the company claims is recyclable, waterproof and less toxic than regular concrete, certainly expects to sell to India.

CEO David Rosenberg told Greentech Media the company will provide concrete for what will be the tallest building in Mumbai, slated to have more than 60 floors. The company already has begun shipping for the project and construction is expected to begin in two months, he said.

India is an "obvious" growth market for Hycrete, Rosenberg said, adding that the company also is targeting Eastern Europe and the Middle East.

"We're picking growth countries, not places with a lot of buildings already," he said.

It might be unintuitive, but customers in those developing markets are willing to use more of Hycrete's concrete, even though it costs more than regular concrete, because they already pay even more to waterproof their buildings now, he said.

Consider India's monsoon season. Buildings in India also tend to include a lot of tile work, resulting in leaks on the floors, Rosenberg said.

So while most U.S. projects only are using Hycrete's concrete for foundations, plaza areas and roofing systems, the Mumbai project is using the concrete for the whole building, he said.