On the coastline near India's southern tip, workers toil on a pier carrying a conveyor belt that cuts a mile into the Indian Ocean, where the azure waters are deep enough for ships to berth and unload huge cargoes of coal.

The belt will carry millions of tons of coal each year to a giant power plant several kilometers inland that will burn the fuel for at least 30 years to generate power for the more than 70 million people who live in India's Tamil Nadu state.

The Udangudi plant is one of nearly 200 coal-fired power stations under construction in Asia, including 95 in China, 28 in India and 23 in Indonesia, according to data from U.S. nonprofit Global Energy Monitor (GEM).