Shanghai had 12 consecutive days with excellent or good air quality by yesterday, but this year's average air quality so far is still poorer than the same period last year, the Shanghai Environmental Protection Bureau said yesterday.

The city's temporary clean air is the result of recent rains that have wiped out pollution particles.

If the city expects better air quality, it needs to take a firmer hand to reduce air pollutants from vehicles' toxic black fumes and industrial chimneys, the bureau said.

Shanghai measures air quality from Grade 1, or excellent, to Grade 5, the worst level, depending on the pollution-causing particles in the air.

Over the past 12 days, the city has had eight days of Grade 1 and four days of Grade 2. So far this year, the city has had 201 days with air quality of either Grade 1 or 2, seven days less than the same period last year.

Normally, the city's air quality from June to September is the best of the year thanks to the wind direction and tropical cyclones. The worst season is from November to February, the bureau said.

Shanghai has announced it will cut emissions from industrial boilers by up to 90 percent over the next three years.

(Shanghai Daily August 22, 2007)