Missile man and former President Dr APJ Abdul Kalam, in the role of an environmentalist, has called upon Delhites to be involved in cleaning of the city's lifeline, Yamuna river. The ex-president is a man of his own stature and thinks very deeply. These days Dr Kalam is busy in social works. As regards the river Yamuna, it has been polluted from whereever it is flowing, near Kanpur, Allahabad and Agra by industrial units established there as also the people living there. Near Kanpur Dehat, the dirty water from leather factories is drained in the river.