Beijing issues first pollution red alert as smog engulfs capital

Alert will prompt schools and factories to close and force millions of vehicles off roads after smog reached 40 times safe level in some areas

Beijing has issued its first pollution red alert as acrid smog enveloped the Chinese capital for the second time this month.

The alert will begin at 7am on Tuesday and should see millions of vehicles forced off the roads, factories and construction sites shut down and schools and nurseries advised to close.