When India shut down last month and suspended all transport to contain the spread of coronavirus, the skies over its polluted cities quickly turned an azure blue, and the air, unusually fresh.
As air pollution plummeted to levels unseen in living memory, people shared pictures of spotless skies and even Himalayan peaks from cities where the view had been obscured by fog for decades.
On one social messaging group, a resident of the capital, Delhi, which regularly records some of the foulest air in the world, celebrated the city's "alpine weather". Politician and author Shashi Tharoor wrote that the "blissful sight of blue skies and the joy of breathing clean air provides just the contrast to illustrate what we are doing to ourselves the rest of the time".