A NEW system that tracks crowds via their mobile phones will be put to the test next month in subway stations, a senior city official said yesterday.

Shao Zhiqing, vice director of the Shanghai Municipal Economy and Information Technology Development Commission, said the country’s leading telecommunications companies — China Mobile, China Unicom and China Telecom — will work with a fourth, unnamed, company to develop the monitoring system.

It will be used to control crowds on the city’s Metro system, he said.