Skip to Content

Cleaner Vehicles by the Million

Last January, for the first time, more cars were sold in China than in the United States. India’s vehicle fleet is growing at a rate of 7 to 10 percent per year. Instead of attempting to reduce greenhouse-gas emissions with expensive technologies such as electric vehicles, low-income countries in the Asia-Pacific region are focused on improving existing internal-combustion engines.

Converting cars to run on natural gas is an increasingly popular option. Of the 9.6 million natural-gas-fueled vehicles worldwide, 52 percent are in Asia-Pacific countries, with two million in Pakistan alone. A factory-built natural-gas vehicle can achieve reductions in carbon dioxide emissions as great as 25 percent, but most of the cars running on natural gas in this region are not quite as clean, because they have been converted from gasoline using after-market kits. Still, these converted vehicles emit half as much nitrous oxide as gasoline-fueled vehicles and three-quarters as much carbon monoxide. Conversion kits cost between $850 and $2,500, but conversion reduces driving costs because natural gas is cheaper than gasoline or diesel. The number of natural-gas vehicles has been growing at an annual rate of 40 percent over the last five years, according to the Asia Pacific Natural Gas Vehicles Association.

Asia is also home to more than 50 million vehicles powered by two-stroke engines, such as motorcycles and taxis. Per mile, each one produces as much in hydrocarbon and particulate emissions as 30 to 50 modern four-stroke automobiles, according to Bryan Willson, a professor of mechanical engineering at Colorado State University. The nonprofit Envirofit has developed a $300 fuel-injection kit that increases fuel efficiency by 35 percent and reduces hydrocarbon emissions by 89 percent. Owners can purchase the kit with microloans, and reduced fuel bills mean it pays for itself in six months.

Keep Reading

Most Popular

AV2.0 autonomous vehicles adapt to unknown road conditions concept
AV2.0 autonomous vehicles adapt to unknown road conditions concept

The big new idea for making self-driving cars that can go anywhere

The mainstream approach to driverless cars is slow and difficult. These startups think going all-in on AI will get there faster.

biomass with Charm mobile unit in background
biomass with Charm mobile unit in background

Inside Charm Industrial’s big bet on corn stalks for carbon removal

The startup used plant matter and bio-oil to sequester thousands of tons of carbon. The question now is how reliable, scalable, and economical this approach will prove.

images created by Google Imagen
images created by Google Imagen

The dark secret behind those cute AI-generated animal images

Google Brain has revealed its own image-making AI, called Imagen. But don't expect to see anything that isn't wholesome.

AGI is just chatter for now concept
AGI is just chatter for now concept

The hype around DeepMind’s new AI model misses what’s actually cool about it

Some worry that the chatter about these tools is doing the whole field a disservice.

Stay connected

Illustration by Rose WongIllustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.