RACHEL MARTIN, HOST:
The pandemic is having some unintended consequences on the environment. There's less air pollution. And now scientists are finding that water quality is improving, too. NPR's Lauren Sommer reports.
LAUREN SOMMER, BYLINE: In normal times, Manhattan sees a huge influx of people every day. They're working and shopping and flushing.
NIMA PAHLEVAN: Manhattan has about just over 2 million commuters not showing up at work and not using the water.
SOMMER: Nima Pahlevan works on remote sensing at NASA's Goddard Space Flight Center. He says all that wastewater normally flows to sewage treatment plants, which clean it up and release it into the Hudson River. That can make the river cloudier. But with all those people flushing toilets elsewhere, the pandemic has made the water clearer.
PAHLEVAN: The change has been over 30% - 30, 40%.
SOMMER: It's enough to be seen from space, which is how Pahlevan measured it.
PAHLEVAN: More clarity in the water that you could see with the naked eye, that's the exact same thing that satellite would see.
SOMMER: The improvement in water quality could be helping the local ecosystem. But Pahlevan says it's tough to say because a lot of scientific fieldwork has been canceled during the pandemic. But he's also looking for water quality benefits in San Francisco and Chesapeake Bay.
PAHLEVAN: So that's really the benefit of this pandemic from the environmental standpoint. Other than that, it's been terrible.
SOMMER: There have been similar changes on the other side of the planet, too.
NED BAIR: You could see the Himalaya from Delhi. That's pretty rare. If you've ever been to Delhi, you can't see anything.
SOMMER: Ned Bair is a researcher at the University of California, Santa Barbara. He says, as people stayed home in India in the spring, air pollution fell. And that didn't just mean that you could see the Himalayas. It actually changed the way they looked.
BAIR: It's a brighter snowpack.
SOMMER: There was less dust and soot landing on the snow, about 30% less. And that made it more blindingly white because it reflects more sunlight.
BAIR: And that, in turn, prevents the snow cover from melting.
SOMMER: So the snowpack melted later in the year, which can be a good thing because 300 million people in the Indus River basin depend on it for water supply. And when the snowpack melts too early...
BAIR: Those streams will go dry. And it'll be a humanitarian crisis because people will not have enough water.
SOMMER: Bair says this natural experiment helps reveal how air pollution is making water supplies around the world less reliable.
BAIR: This whole pandemic in general has really showed us, in a fast way (laughter), how we are affecting our water supply with pollution.
SOMMER: And that's information that could help scientists make the case for lasting changes in the future.
Lauren Sommer, NPR News.
(SOUNDBITE OF LAPA'S "DOG WALKER") Transcript provided by NPR, Copyright NPR.
