(HONG KONG-AFP) - Hong Kong's first battery-powered public bus took to the streets Monday as part of a drive against the city's choking pollution.

Chief executive Leung Chun-ying has pledged to make pollution one of his top priorities during his five-year term, with an official report saying it was the "greatest daily health risk" to the city's residents.

But at least one local environmental group was sceptical about the government's anti-pollution commitment, saying "one bus wouldn't make any difference" and that Hong Kong was lagging behind other global cities when it came to electric vehicles.