9 November 2019 | New Scientist | 5A 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 HealthEffects 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 VaughanEnvironmentChemical 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 ScullyIndia chokes on dirty air
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