The Hong Kong Polytechnic University has teamed up with the US National Aeronautics and Space Administration to give researchers access to daily satellite images of the region and the world, the Hong Kong Standard reported.

"What surprised us is that when we compared pollution in Hong Kong on a normal day, it was always higher than other cities like Taipei, Paris and Washington," associate professor Janet Nichol told the paper.

However, she added that smog pollution in Beijing was sometimes worse.

Hong Kong has seen its air pollution levels rise sharply over the past decade, largely because of pollution blown over the border from neighbouring industrial southern China.

Tung Chee-hwa, former chief executive of Hong Kong, had declared tackling pollution a priority policy eight years ago, but the government has been unable to implement effective measures to ease the smog.

--DPA