While the instructions for containing the spread of the virus sound fairly simple — wash your hands for 20 seconds with soap multiple times a day — it is not an easy task for the majority of Pakistan's informal settlements that are water deprived. Access to water varies massively.

People living in Karachi's Machar Colony, an informal settlement at a considerable distance from the city centre, pay Rs7,000-8,000 a month in water purchased through tankers and other informal means. Residents of Gharibabad, near Karachi's PIDC, spend over Rs5,000 a month on the same. For poor households, this is a very significant portion of their earnings. The idea of using that water repeatedly for washing hands is a luxury.

Here are some basic calculations on daily water use for maintaining hygiene:

Read the full story on why Covid-19 is an urban crisis here.