Chennai on Friday joined Mumbai, Delhi, Kolkata and Bangalore in launching free SMS alerts on traffic for the public. Those wishing to get regular alerts on the traffic situation on their mobile phones can send an SMS JOIN CTP to 09219592195, police said.

The service is free of cost, except for the first SMS sent for registration. However, this service would not be available to those who have activated the 'Do Not Disturb' service, they said.