Union Minister Ram Vilas Paswan hit back at Delhi Chief Minister Arvind Kejriwal today in an escalating war of words over the 'poor' quality of drinking water in the national capital. The feud between the two leaders was triggered by a BIS report that said tap water in Delhi, Chennai and Kolkata failed 10 of 11 parameters. Mr Paswan, who is the Consumer Affairs Minister, strongly denied Mr Kejriwal's claims the report was "false and politically motivated" and challenged the AAP chief to name officials to a joint team to re-test drinking water in the city state.