BEIJING (REUTERS) - China's commercial capital, Shanghai, introduced emergency measures to tackle air pollution on Wednesday, allowing it to shut schools and order cars off the road in the case of severe smog, Xinhua state news agency said.

Shanghai was blanketed with record levels of smog last month, while air in the usually more polluted capital, Beijing, was relatively clear. The government warned children and the elderly in Shanghai to stay at home on some days.

Xinhua said that Shanghai reviewed and approved the "special emergency pollution plan" on Wednesday.

China regularly issues directives to tackle pollution in major cities, but efforts so far to clean the air have failed.

Air quality is of increasing concern to China's stability-obsessed leaders, anxious to douse potential unrest as a more affluent urban population turns against a growth-at-all-costs economic model that has poisoned much of the country's air, water and soil.

Authorities have invested in various projects to fight pollution and empowered courts to mete out the death penalty in serious cases.

But enforcement of rules has been patchy at the local level, where authorities often rely on taxes paid by polluting industries.