New Scientist - USA (2019-11-09)

9 November 2019 | New Scientist | 5

A SEVERE episode of smog in large

parts of northern India has forced

authorities to impose traffic

restrictions, cancel dozens of

flights and close primary schools.

Levels of tiny particulate pollution,

known as PM2.5, spiked over the

weekend in the capital, Delhi, to

more than 10 times safe limits.

Such extreme pollution occurs

every year in the region, usually

between October and November,

as a result of weakening winds,

falling temperatures and farmers

burning the stubble of crops.

“You can almost count on

something of this magnitude

happening,” says Joshua Apte at

the University of Texas at Austin.

The current crisis isn’t even the

worst India has suffered: in 2016,

Delhi was hit by a week of smog.

Agricultural fires were the single

biggest cause of pollution in Delhi

on Monday, contributing 38 per

cent of it, according to modelling

by independent air quality

researcher Sarath Guttikunda.

But Apte says it would be wrong

to focus on farming because

things such as vehicles, power

plants and household wood-

burning are also big sources. “Even

on a good day, the air in north

India is among the most severely

polluted on the planet,” he says.

The smog isn’t only in Delhi,

says Pallavi Pant at the Health

Effects Institute in Massachusetts.

“There are smaller towns and

villages across the northern part

of the country that are facing

equally dire pollution.”

For now, little can be done short

of waiting for winds to shift the

smog. In the longer term, both

Apte and Pant say India must

implement stronger pollution

controls across a range of sectors.

Delhi is the 11th worst city in

the world for annual PM2.5 levels,

according to the World Health

Organization. It says that almost

half of the planet’s 50 most

polluted cities are in India. ❚

Levels of air pollution are spiking in northern India and environmental

controls are lacking, reports Adam Vaughan

Environment

Chemical lawsuit

set to hit Australia

UP TO 40,000 residents of

towns contaminated with

chemicals from firefighting

foams are set to sue the

Australian government,

making it the biggest class

action lawsuit in the

country’s history.

The chemicals, called

PFAS (perfluoroalkyl and

polyfluoroalkyl substances),

were used in firefighting

foams on military bases

in the 1970s. They were

phased out in Australia in

2004 after studies showed

they tended to accumulate

in people’s blood, but

they are still found in

some waterways used for

drinking and agriculture.

The lawsuit will argue that

properties near the bases

have lost value as a result.

PFAS don’t easily break

down. Studies in lab animals

suggest that extended

exposure to high levels of

some may cause cancers,

but it is still unclear how

this translates to humans.

The Australian

government has warned

people in some communities

not to drink from waterways

or bore water, eat fish or

consume produce grown

on nearby farms. But the

website of the government’s

defence department says

the health effects of PFAS

are “generally small and

within normal ranges for

the whole population”.

“It’s an extraordinarily

confusing message,”

says Erin Brockovich,

an ambassador for

Shine Lawyers, the firm

bringing the case. ❚

Ruby Prosser Scully

India chokes on dirty air

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