About a thousand taxis running on the city streets received these cards on Wednesday.

This step has been taken jointly by the Bengal Taxi Association and Concern for Calcutta, a citybased NGO, to help passengers who want to trace a taxi they hired on an earlier occasion.

"Each taxi driver has been given about 150 complaint cards. This has been done to facilitate passengers in tracing the taxi," said Bimal Kumar Guha, general secretary of the Bengal Taxi Association.

But the Principal Secretary of the state Transport department, Sumantra Choudhury, said this system of helping passengers might run into hurdles.

Expressing his doubt over the efficacy of this step, Choudhury told The Indian Express that: "It is a good idea. But I doubt if it will be implemented successfully. It is a difficult task to monitor and check if the drivers are following it."

The distribution of complaint cards depends entirely on the drivers. Apart from the complaint cards, taxi drivers have also been asked to display the fare conversion chart.

Though the rule of displaying the chart was made mandatory years ago by the Transport department, very few taxi drivers bother to display it for the convenience of passengers.

"We tried to make this step mandatory on earlier occasions.