The rise in air pollution levels in Indian megacities between 2002 and 2010 has been much more than Chinese urban centres. It was also the highest among 189 cities analysed by the Tel Aviv University, using NASA's high-tech aerosol monitoring satellites.

The study, using data from three different satellites, showed that particulate matter - caused by dust and vehicular emissions - increased by more than 10% in most Indian cities whereas the maximum increase of 5 to 10% was witnessed only in northern Chinese cities.

"The increasing aerosol trends over the largest cities in the Indian subcontinent, West Asia, and North China can be clearly seen. By contrast, megacities in Europe, the northeast of US, and South-East Asia show mainly declining trends," said the study, released by the American Journal of Climate Change this week.

Bangalore, the 'Indian Silicon Valley', earned the dubious distinction of witnessing the second-highest increase (34%) in air pollution levels among 189 cities, after Portland in the US.

Other Indian cities that recorded a high increase in air pollution levels were Pune at 27%, Nagpur at 22%, Mumbai at 18%, Bhilai at 17.7%, Surat at 12.5% and Ahmedabad at 12%.

However, the usual culprits - Delhi and Kanpur - recorded just 4.2% and 6.5% increase in particulate matter.

The data captured by satellites hundreds of metres above the ground show a different picture than information gathered through ground monitoring.

Also, high atmospheric aerosol concentration in space modifies cloud properties, leading to less rainfall, and dimming of solar radiation in cities. "Data show that solar radiation over big cities with high population concentration has reduced, causing its own health problems," the study said.