Worried that current pollution curbs may not be enough to clean the air, China yesterday announced a raft of emergency measures it would take if skies fail to clear up further for the Olympic Games, including more factory shutdowns and increased restrictions on cars.

The polluted air, one of the biggest worries for Olympic organisers, prompted Beijing to begin drastic measures earlier this month, including pulling half the city's 3.3 million vehicles off the roads, halting most construction and closing some factories in the capital and surrounding provinces.

The new emergency measures include shutting another 200-plus factories and further restricting vehicles across Beijing, Tianjin city and surrounding Hebei province, according to a public notice posted yesterday on the government's website.

Shut temporarily

In the capital, an additional 105 machinery, chemical and construction materials factories would be shut temporarily. In Tianjin, 130 kilometres (80 miles) east, 56 factories would be closed, while 61 factories would be shut in Hebei.

In Beijing, besides current restrictions banning odd/even licence plates on alternate days, automobiles whose last digit matches the last digit of the date would be banned. Tianjin and Hebei would begin implementing similar odd/even restrictions.

In addition, all construction sites across Beijing would be halted.

The notice said once the games begin August 8, the contingency measures would kick in if authorities decide the air quality had not improved enough.

"If there are unfavourable weather conditions, and the air quality is forecast to not meet the standards in the following 48 hours, the operating commanding centre would suggest the contingency plans be initiated," it said.

Yesterday, the pollution index rose up to 69, but remained within the national standard for acceptable air.

A day earlier, the city's air pollution index had dropped to 44, less than half what it was on Tuesday, and the lowest since July 20 when the first measures came into effect.

A cooling wind and some rain earlier this week helped sweep away pollutants and gave Beijingers a respite from the sultry heat and humidity that had cloaked the city for days.

Desired effect

The measures are having the desired effect, Du Shaozhong, deputy director of Beijing's Environmental Protection Bureau, told The Associated Press in an interview.

"The daily data since July 20 shows an improvement in air quality. It reflects the results since we restricted traffic and stopped heavy-polluting factories and construction," he said. "That's why we say the measures have been effective."

A reading below 50 is considered good and between 51 to 100 is moderate. But critics say even moderate levels are still above the World Health Organisation's guidelines for healthy air.

Some experts argue that the recent weather conditions, not the curbs, were largely responsible for the cleaner air.