Beijing will continue to face tough environmental challenges after the Olympics and will adopt stricter measures to cope with pollution, an environment official said on Saturday.

Du Shaozhong, deputy director of the Beijing Environmental Protection Bureau, told a press conference that some of the temporary pollution-curbing measures would become permanent after the Games.

"For example, we will accelerate the removal and treatment of heavily-polluting vehicles, and step up construction site dust reduction," he said. "Project builders in Beijing must increase their input in environment protection."

Pollution had been a major concern in the run-up to the Games. To improve the air quality, the capital pulled half of its 3.3 million vehicles off the road with even-odd licence plate number restrictions as one of the temporary measures, which included closing polluting factories in Beijing and neighboring provinces, the suspension of most urban construction projects, and the removal of vehicles failing to meet emission standards.

Du said that since the Games opened on August 8, the city's air quality ranged between excellent and fairly good on the pollution index, the cleanest for any summer period in the last 10 years.

However, "our happiness and easiness are limited", he said. "Although the Olympic Games will end soon, the environmental challenges we face are by no means over."

The city authorities will requires heavily-polluting enterprises to resolve their pollution problems as a prerequisite to resuming operations after the Games, Du said.

"If they can't resolve the  pollution problems, they should stop or limit their production," he said.

The official called for public involvement in pollution control. "We'll draw experience from the Olympics to organize volunteers to get involved in the daily environment protection administration, and continue to reward those who report illegal pollution activities."