Hong Kong, Nov 25 (DPA) The Hong Kong government Wednesday warned people with respiratory illnesses to limit their time outdoors as air pollution in the city soared to potentially dangerous levels.

Pollution readings at roadside monitors recorded very high levels Wednesday morning as a dense winter smog, triggered largely by factory fumes from neighbouring China, enveloped the city of seven million.

Hong Kong has been plagued for more than a decade with worsening pollution despite government efforts to clean up the air by making taxis and buses use environmentally friendly fuels.

Eighty percent of the city’s smog comes from the vast industrial belt of Guangdong in neighbouring southern China, experts said.

A recent survey found that most Hong Kong people believe air pollution is worsening but less than half want to pay more for buses or electricity in an effort to ease the problem.

University studies have found that the persistent smog in Hong Kong is driving away foreign investors and jeopardising the health of tens of thousands of residents.