New | Shanghai grinds to a halt as smog nears top of air pollution scale
Flights scrapped, roads closed and construction stopped as pollution hits east and south; no relief expected until Sunday at the earliest
Shanghai experienced one of its worst episodes of air pollution on Friday, with the air quality index reaching the "severe" level, the worst on a six-tier national rating system.
In the Pudong district, home to multinational businesses and financial services companies, the level of PM2.5 - fine particles smaller than 2.5 microns in diameter which pose the biggest health risk - exceeded 600 micrograms per cubic metre by 1pm. In Putuo district, the level exceeded 700 mcg per cubic metre. The World Health Organisation safe limit is 25 mcg per cubic metre.
Overall air quality was considerably worse than the municipal government had anticipated on Thursday when the bad pollution began. It had forecast the index would be at 240 to 310 on Friday afternoon.
With such a high concentration of air pollutants, the authorities warned even healthy people would show some serious health symptoms and be more vulnerable to disease.
Children, the elderly and the sick were advised to remain at home, while others were told to reduce their outdoor activities as much as possible.
Some of the worst polluting factories were told to limit or stop production. Building and road construction work was halted and nearly a third of government cars were pulled out of service.
