Delhi's Car Limits Won't Clean Up City's Filthy Air

@ CNN - New Delhi is preparing to pull millions of cars off its streets for the second time this year as the local government searches for a way to improve air quality in the world's most polluted city. The driving restrictions, dubbed "odd-even," will limit drivers to using their cars on alternate days for two weeks starting Friday. The idea is that fewer cars on the road will reduce vehicle emissions and improve air quality.

Just one problem: Experts say the program will likely have only negligible benefits, and is a far cry from the comprehensive approach needed to markedly improve air quality in the megacity of 20 million. "People are just rallying behind a feel-good policy," said Rahul Goel, an assistant professor at Shiv Nadar University, who studied traffic patterns during the initial phase of "odd-even" in January. Goel's team found that while car traffic eased during the experiment, potential emissions improvements were offset by an increase in the number of motorcycles and autorickshaws on the road. A second study, conducted by researchers from the University of Chicago, found there was a 10% decrease in air pollution levels during the program's initial phase.

"Did it work in January? With a bunch of caveats, yes," said Santosh Harish, assistant director of EPIC India, who noted that changes in weather and commercial traffic patterns can make it difficult to identify the source of air pollution improvements.