The capital's pollution regularly reaches hazardous levels.
The often hazardous levels of air pollution in some cities regularly make headlines worldwide.
Under a stricter state of California test, they also leached four other metals above hazardous levels.
Delhi is not the only city this week to respond to hazardous levels of air pollution with a transport initiative.
Industry officials said that even if the lead was not at hazardous levels, they wanted to eliminate it.
Last week more than 200 Malaysian schools were forced to close, and pollution twice reached officially hazardous levels.
On Thursday, air pollution in the capital soared to hazardous levels.
City residents have previously criticised authorities for being too slow to issue red alerts for heavy smog, which often exceeds hazardous levels on pollution indices.
Last week, Beijing once again suffered hazardous levels of air pollution prompting the city's mayor to announce an "all-out effort" to tackle the smog.
By Monday afternoon there had been a slight improvement, although air quality remained at "hazardous" levels in Shenyang, an industrial city of about 8 million inhabitants.
Mattel announced a global recall of 848,000 toys last night, the company's third recent recall because of hazardous levels of lead paint on toys.
