New York City mayor Michael Bloomberg has this week revealed that the city is to accelerate its drive to cut emissions from its taxi fleet, announcing plans to buy up to 300 new hybrid cars a month.

According to Reuters reports, the city's Taxi and Limousine Commission has reached an agreement with Nissan for it to provide 200 of its Altima hybrids each month, while GM has promised to deliver 50 Chevrolet Malibu hybrids and Ford has pledged 50 of its Escape hybrids.

The deals put the city on track to reach its goal of delivering an all-hybrid taxi fleet well ahead of its initial target date of 2012.

Taxi and Limousine Commission chairman Matthew Daus said there are already more than 1,300 hybrid taxis in operation in the city and that they are already delivering significant benefits with each one saving drivers about $6,500 (£3,300) a year in fuel costs.