Sponge cities - Xi's plan becoming a reality

In 2013, President Xi Jinping introduced a new term to the global green glossary - "sponge cities."

In doing so, he was addressing a problem urban planners had long struggled with - how to prevent rainwater from flooding cities. But Xi was also looking at ways of conserving water, instead of just sending it down the drain.

Until then, much of the global effort had been focused on draining rainwater out of cities as quickly as possible via pipes and canals to avert flash floods. Only piecemeal measures had been taken to secure it.