Even as petroleum companies race to meet the October 2 deadline to fully introduce unleaded petrol (ULP) all over Mumbai, the question remains - how much is simple shift to ULP going to reduce the city's air pollution problems? Speptics, say the 'no lead, no worries' mantra is too seductively simple; unless other measures are taken, pollutants such as benzene, carbon monoxide and other hydrocarbon emissions will continue to be dangerously high.