A cleaner river runs through it

One of the dirtiest rivers in Malaysia is not so dirty any more, thanks to the movement control order (MCO) imposed to control the spread of the coronavirus. The photographs were taken by a drone over Sungai Pinang in Georgetown, Penang. They were taken on March 8 and April 26 at low tide to make a fair comparison. The 3.5km river, whose water quality was categorised at Class Four (top), just one step below the dead river category of Class Five, is now jade green (above). Professor Chan Ngai Weng, who researches environmental management and hydrology at Universiti Sains Malaysia, said the pre-MCO pollution was down to human activity.