Concerns about pollution in Hong Kong are growing, after the city experienced its worst air quality on record in March, when the city's harbor was cloaked in thick smog, blamed on sandstorms from northern China.

Hong Kong's Environmental Protection Department said local air pollution indices soared to levels of around 500, smashing the previous record of 202 recorded in July 2008. A reading above 51 is considered high. Residents with heart and lung diseases were urged to avoid outdoor activities as the readings were described as "severe."

[Joanne Ooi, CEO, Clean Air Network]:
"I think that the dust storm at the end of March actually brought the public and the government closer to a tipping point, because for the first time, everybody in society was actually extremely concerned for their health. And that includes outdoor workers, blue collar workers, drivers, people who ordinarily would think: 'Air pollution doesn't affect me or I shouldn't care about it.’"

According to the Hedley Environmental Index, which monitors and publishes in real-time the economic costs of Hong Kong's air pollution, the bad air would have resulted in 322 premature deaths and 2.5 million visits to the doctor so far this year.

While officials have striven to clean up vehicles and power stations locally, pollutants blown in from tens of thousands of factories in southern China's manufacturing and export hub on the Pearl River Delta have also had a serious impact on air quality.

[W.C. Mok, Assistant Director, Environmental Protection Department]:English
"We have also proposed to the legislature to see what we can to introduce these incentives, for example raising the license fee of aged commercial vehicles such as to provide extra driving force to these vehicle owners to replace their aged vehicles. We believe these measures, the replacement scheme, can be really effective in improving the air quality on the roadside."

But on the streets of Hong Kong, where facemasks are a common sight, people are not convinced by the government's overtones.

[Hong Kong Resident]:
"Hong Kong's air is too polluted, very dirty, not enough oxygen. That's why I need to wear the facemask. It's unbearable because people also smoke everywhere."

Hong Kong's streets are some of the most crowded in the world,

[Hong Kong Resident]:
"Actually the government can tackle the problem by looking at public transport. Especially the buses and the ferries – they are emitting a lot of bad gases which pollute our air. This is an area which I think should be tackled as soon as possible."

with almost 280 vehicles for every kilometer of road.