India and China are the world’s biggest polluters but the times are changing. According to NASA, both the countries have put extensive efforts into making their land greener.

The report says there are now more than 2 million sq miles of extra leaf area per year, compared with the early 2000s- a five percent increase. This is due to the ambitious tree-planting and intensive farming in both countries.

Satellite data from the US space agency Nasa shows that over the last two decades there has been an increase in leaf area on plants and trees equivalent to the area covered by all the Amazon rainforests.

The greening was first detected in the mid-1990s.

“In the 1990s, people realized it, and today things have improved,” says Rama Nemani, a research scientist at NASA’s Ames Research Center and a co-author of the study. “Humans are incredibly resilient. That’s what we see in the satellite data.”

Scientists first assumed plants were being fertilised by the extra CO2 in the atmosphere and boosted by a warmer, wetter climate.

But they didn’t know whether changes in farming and forestry were contributing to the changes.

Thanks to a Nasa instrument called Modis, which is orbiting the Earth on two satellites, they can now see that both are clearly playing a direct part, too.

China’s contribution to the global greening trend comes in large part (42%) from programmes to conserve and expand forests. Long-since plagued by heavy air pollution, China has recently been making efforts to cut back on land degradation and minimize pollutants in the region

Another 32% of the greening there – and 82% of the greening in India – comes from intensive cultivation of food crops thanks to fertilisers and irrigation.

Production of grains, vegetables, fruits and other crops has increased by 35% to 40% since 2000, so both nations can feed their large populations.

“China and India account for one-third of the greening but contain only 9 percent of the planet’s land area covered in vegetation,” said lead author Chi Chen of Boston University. “That is a surprising finding, considering the general notion of land degradation in populous countries from over exploitation.”