India’s lethal air has become so routine that even mass mortality now struggles to provoke political urgency.   India’s national capital is choking as it always does, under a winter blanket of smog that has long ceased to shock. Delhi Chief Minister Rekha Gupta has responded by urging half the city’s office workforce to work from home - a palliative that only serves to starkly underscore the enduring helplessness of governments in tackling the poison in the air. Delhi is not the only city...