Air pollution is getting worse in India and across Asia. Already it’s weakened economic growth and caused premature deaths. It even threatens India’s ability to produce enough food for its population. But there are solutions.

Smog over northern India has worsened since this 2004 photo was taken. (NASA)

Climate scientist V. Ramanathan calls this “shocking.” He’s researched atmospheric science for decades at the University of California, San Diego, and elsewhere. His advice: Act now.

In a recent study, Ramanathan and co-author Jennifer Burney find that 36 percent of crops in India are destroyed by chemical damage from ozone and the effects of black carbon pollution. In some Indian states, losses are 50 percent. “We spent a year redoing our calculations to be sure that we did not make any mistakes,” Ramanathan said.

V. Ramanathan, left, and other researchers meet Pope Francis at the Vatican in 2014. (Pontifical Academy of Sciences)

Why is this happening?

Car and truck exhaust, outdoor fires and biomass-burning cookstoves all pollute the air. Plants exposed to ozone wither away, decreasing crop yields. Particulate pollutants like black carbon, Ramanathan said, intercept sunlight and reduce precipitation. That means lower yields of rice and other rain-dependent staples.

Using 2005 data, scientists have concluded that ozone pollution alone kills crops that could feed 94 million people. Air pollution in India has gotten worse since then, so today’s figure likely is even higher.

Ground-level ozone from motor vehicles is toxic to plants. Black carbon from vehicles and burning biomass disrupts the rain cycle by interfering with sunlight. (State Dept./Doug Thompson)

Losing billions of rupees’ worth of wheat, rice and cotton crops is not the only problem. There is a significant uptick in pollution-related diseases and the medical costs that follow.

But “solutions are available,” according to Ramanathan. “They are reasonably straightforward. They cost, for sure. But when you factor in the cost of human health and climate change, the cost of improving the air is much, much, much smaller.”

Daily ozone exposure damages and kills plants. (ARS/USDA)

What are the fixes?

Striking at ozone and black carbon will bring fast results. “You don’t have to wait for 20 or 30 years; the effect will be immediate,” Ramanathan said.

Several technologies can help. Wide use of efficient, low-emissions cookstoves in cities and villages is key. Women like the more efficient stoves, Ramanathan said, as this video details, but they cannot afford them. Targeted microfinancing or subsidies could help.

Fitting trucks with diesel particle filters — which can be made in India, Ramanathan notes — and mandating low-sulfur diesel fuel would minimize pollutants.

Farmers can make a huge difference by not burning agricultural waste likes rice straw and wheat stubble. (Restriction of outdoor burning, among other strategies, improved Los Angeles’ air quality.)

Ramanathan believes in acting now and involving everybody. We need to “convince people to solve the problem,” he concludes.