Delhi 'odd-even' car policy fails to curb pollution

The New Year saw the introduction of what the authorities in the Indian capital call an "odd-even" number plate scheme. It is a pretty simple idea: number plates that end in an odd number can only drive on odd-numbered days, even numbers on even-numbered days.

In theory that should halve traffic numbers, but a host of exemptions means many more than half the nearly nine million vehicles registered in the city can still take to the roads every day.

Nevertheless, congestion is noticeably down, and very pleasant that is too.

But sadly the same doesn't appear to be true of air pollution - the target of the new restrictions, reports Justin Rowlatt.