Temeperatures on the Chinese territory's public transport and in its malls reached as low as 16 degrees Celsius (61 Fahrenheit), Friends of the Earth Hong Kong said in a Sunday statement.

"Excessive air conditioning will only result in extra emissions of air pollutants and greenhouse gases, which could have been avoided," the statement said.

Earlier this month the group launched a campaign encouraging the public to register complaints about places that exceed the government-recommended 25.5 degrees Celsius (78 degrees F) limit in public buildings or vehicles.

It said of the 266 complaints received, 24 percent referred to bitter-cold buses and 20 percent to shivering shopping centres.

The green group said Hong Kong's interiors were the coldest in the world and pointed to a number of travel guides, including the hugely popular "Lonely Planet" series, which warn travellers of the arctic condtions in Hong Kong's buildings.

Ironically, one of the worst offenders was the city's tourism promotion office, which registered a chilly 19 degrees, Friends of the Earth said.

"I don't think we want to leave a bad impression on tourists for our extravagent energy consumption and our indifference to the environment," Hahn Chu Hon-keung, the group's environmental affairs officer, said in the statement.

The report comes amid rising concern about air and water pollution in the former British colony.

Last year saw a dramatic increase in the number of days when visibility was substantially reduced by smog. Travel bosses here were angered when articles in British newspapers last year labelled the city a health hazard.

The vast majority of the pollution drifts in from the heavily industrialised Pearl River Delta region of neighbouring southern China.