Air pollution is "a matter of life and death," DPA quoted Hong Kong's leader Donald Tsang as saying Thursday in his strongest comments to date on the smog that regularly envelopes the city. Chief executive Tsang admitted Hong Kong's competitiveness would suffer in the long term if it failed to reduce air pollution which is so bad on some days it is impossible to see from one side of Victoria Harbour to the other. However, he denied suggestions that foreign firms were already staying away from the city of 6.9 million because of its poor air, saying Hong Kong was the biggest regional recipient of foreign direct investment. Speaking on a phone-in show taking calls from members of the public over his policy address speech Wednesday in which he was criticised for failing to address air pollution, he pledged to leave the city with cleaner air when he steps down in 2012. Tsang has been criticised for taking the pollution issue too lightly in the past. Only weeks ago he boasted there had been "blue skies" since he was re-elected earlier this year for a full five-year term. Soon after his comments, Hong Kong suffered some of its highest levels of air pollution with palls of smog regularly cloaking the city and people with breathing difficulties warned to avoid spending too much time out of doors.