India, Nov. 6 -- The train engine hoots out a long wail. The sound drifts far up into the afternoon's smoggy air, disintegrating slowly. The express gives a sudden jerk, and the red coaches start to move, slowly leaving the station. The train will go past the shunting yards, past the grimy backwalls of tall buildings, past the slums, past the suburbs, and will soon be out of city limits. The train passengers will break free from Delhi. And from Delhi pollution. Many of us have built our life on the soil of this city. There are times, though, when the idea of quitting Delhi demands a serious consideration. Such as during these days of extreme pollution. The factor is forceful enough for us to return to this picturesque road bridge in Delhi's...