The screenshots began to circulate on Delhi WhatsApp groups last week, captioned with varying expressions of disbelief. Having checked the air quality index, something of a sadistic morning ritual among residents of India’s capital, most could not believe their eyes.

Gone was the familiar menacing red banner, indicating how each intake of breath is really just another toxic blast on their lungs, replaced instead by a healthy, cheerful green. Could it really be that Delhi’s pollution levels now fell into the category of … “good”?

Delhi is ranked as the most polluted capital in the world, with air pollution sometimes reaching life-threatening levels in its urban surroundings. But the now two-week-long nationwide lockdown has not only brought the freshest air the capital has breathed in decades but has also brought back the blue in the skies.

And it’s not just Delhi experiencing the clearest skies in years. Residents in the northern state of Punjab woke up to an incredible sight in the distance. The snowy peaks of the Himalayas were now visible from their homes — a view that had not been on the Punjab horizon for almost 30 years.

The lockdown silver lining also goes beyond India, with toxic megacities such as Bangkok, Beijing, São Paulo, and Bogotá, where varying coronavirus restrictions have been imposed, all reported an unprecedented decline in pollution.

Only a few months ago, Thailand’s capital Bangkok had closed schools because the pollution got so bad. But in the absence of cars on its streets, air quality in the city has improved significantly. The same goes for South America’s most populous city of São Paulo, where notorious traffic queues and smoggy horizons are also giving way to calm streets and clearer skies.

This positive environmental impact of the pandemic has also reached Los Angeles. The city is experiencing its longest stretch of good air quality since 1995, as highway traffic has dropped 80 percent throughout the entire state of California.

As we continue to battle with the pandemic, these unintended positive outcomes provide a nice glimpse into the benefits of moving our societies into a sustainable future.