Terming the Chennai rain fury as a 'natural disaster of unprecedented scale', Union Environment Minister Prakash Javadekar today said it provides a lesson to improve urban planning and improve city governance.

"Chennai is a natural disaster of unprecedented scale... Chennai gives a lesson and we must learn from this lesson and improve our urban planning and improve the City governance which is very essential," he said.

Asked if he describes it as a phenomenon of climate change or a man-made disaster, he said 'that is a grey area' as experts have a different opinion on whether it is climate change event.