STOCKHOLM/SHANGHAI Swedish activist Greta Thunberg joined calls on the 50th anniversary of Earth Day on Wednesday for a combined effort to tackle the coronavirus pandemic and the climate crisis.

Dramatic improvements in air and water quality as coronavirus lockdowns have cut pollution have prompted calls for a low-carbon future, but the need to get millions back to work is clouding the environmental picture.

With economies round the world shut down, wildlife has returned to city streets, with wolves, deer and kangaroos spotted on thoroughfares usually teeming with traffic.

Fish have been seen in Venice canals no longer polluted by motor boats, while residents of some Indian cities have reported seeing the Himalayas for the first time in decades.

Satellite imagery has shown significant air quality improvements across Europe and Asia, including China, where the coronavirus pandemic emerged.

But residents in some of Chinas most smog-prone cities said they feared that blue skies would not last as the worlds second biggest economy got back to work.

In the second half of the year, when the epidemic eases, the weather will slowly be worse after factories reopen, said Tang Zhiwei, 27, a resident of Shanghai. Try your best to enjoy the blue sky now.