India rides on two wheels. The country is the world’s largest market for motorcycles, scooters, and mopeds, which account for 80% of its total vehicle sales. Last year, 15 million two-wheelers were sold in India, more than in any other country in the world.

And yet the market has ample room for further growth: Only 12% of India’s population owns a two-wheeler. Bhavish Aggarwal, who founded India’s leading ride-sharing platform, Ola, at the end of 2010, sees that as an enormous business opportunity—but one with a catch.

If India’s millions of future two-wheel drivers buy gas-powered vehicles, the nation’s cities—already some of the most polluted in the world—will be choked with smog. “We simply cannot allow that to happen,” Aggarwal declares. “So moving to electric vehicles is no longer optional, it’s crucial.”

Thus, a decade after its founding, Ola is now building the world’s largest electric two-wheeler factory in Krishnagiri, a city in India’s southern Tamil Nadu state, about a two-hour drive southeast from Bangalore. The factory is a project under Ola Electric, a new company group launched in 2017.

When the sprawling factory is fully operational, it will be able to produce 10 million two-wheelers a year—15% of the world’s total production. The first phase of the factory, with an annual capacity of 2 million, is near completion; the first batch of electric scooters rolled out on Aug. 15. The company plans to open sales from Sept. 8.

Aggarwal is looking beyond the Indian market. Ola Electric plans to sell electric two-wheelers in Europe, Southeast Asia, and elsewhere. “We will build in India and make for the world,” the 35-year-old entrepreneur told Fortune.

More than a dozen Indian manufacturers have joined Ola in the race to build electric two-wheelers. Among the other leading contenders: Ampere Vehicles, Ather Energy, Bajaj Auto, Hero Electric, and Okinawa Autotech. So far, no company has been able to establish a clear lead. The segment remains a tiny niche of the overall market, but analysts say it is poised for dramatic growth.

In the financial year that ended March 2021, the total number of electric two-wheelers sold in India was 143,837, according to the Society of Manufacturers of Electric Vehicles, an industry association representing India’s EV makers.

That’s a fraction of India’s total two-wheeler sales, of which about a third were scooters.

Yet analysts expect robust growth over the next several years thanks to generous government incentives and subsidies. In June, India’s federal government raised its subsidy on electric two-wheelers to 15,000 rupees per kilowatt-hour of battery capacity, a 50% increase over the previous subsidy. The government has also raised the cap on financial incentives for electric two-wheeler makers to 40% of the cost of the vehicle, up from 20% earlier.

The governments of many states, including Gujarat, Rajasthan, and Maharashtra, have announced additional subsidies.

Suraj Ghosh, associate director for powertrain and compliance forecasts at IHS Markit, a London-based information services provider, says he expects many more states to announce subsidies for electric two-wheelers over the next several years. The segment’s growth, he predicts, will be “phenomenal.”

Ola Electric says its mission is to make gasoline-powered two-wheelers obsolete within the next four years.

It’s an ambitious goal. To achieve it, the company must offer customers a superior combination of price and performance. Ola’s first electric scooter models have been priced at $1,369 and $1,780. In Gujarat, which offers the most generous sweeteners for electric scooters, the after-subsidy cost of buying an Ola scooter falls to as low as $1,064.

That’s comparable to the price of a top-end gasoline-powered scooter and at least 15% to 20% cheaper than electric scooters with similar specifications offered by Ola’s rivals.

Ola’s top-of-the-line S1 Pro scooter boasts a maximum speed of 115 kilometers per hour and a range of up to 181 kilometers on a single full charge.

That range and speed should be sufficient for urban commuters who typically commute no more than 30 to 40 kilometers a day, according to analysts.

Ola scooters also come with features such as navigation maps, keyless locking, and built-in speakers designed to appeal to urban commuters.

But Ola will face stiff competition from established manufacturers like Hero MotoCorp, which has been the world’s largest maker of two-wheelers for the past 20 years and plans to launch its first electric model early next year. Ola must also contend with emerging players such as Bangalore-based Ather Energy, in which Hero MotoCorp owns a 35% stake. (Hero MotoCorp, formerly Hero Honda, is a separate, rival company to Hero Electric.)

Ola Electric has “created a buzz, and the pricing also is adequately aggressive, but to get a product in the market and give the right value to the Indian customer is a different proposition,” said IHS Markit’s Ghosh.

Getting consumers to test that proposition will be all the more challenging given that Ola, unlike established manufacturers such as Hero or Bajaj, doesn’t have a nationwide network of dealerships where customers can kick the tires and take scooters for a test-drive. Ola hopes to sell its scooters with an online strategy, enabling customers to book a test-drive using their smartphone or computer and arrange for an Ola salesman to bring a scooter right to their doorstep. The company will also have physical “experience centers” at select locations.

Another challenge for Ola will be India’s dearth of electric charging stations. Ola plans to install 5,000 charging points in 100 Indian cities within its first year of sales. Aggarwal has vowed to build an “Ola Hypercharger Network” with more than 100,000 charging points across 400 cities, which would make it the widest and densest two-wheeler charging network in the world. Ola says its charging stations will only be accessible to Ola scooters.

Electric vehicle makers will simply have to make the charging infrastructure they want, says Aggarwal. “I don’t think it’s the government’s job,” he tells Fortune.

Ola executives say chargers at its stations will be capable of delivering a half charge in 18 minutes. Consumers also will be able to recharge with a 750W portable charger that comes with the scooter and can be easily installed at home or at the office. The portable chargers can provide a full charge in about six hours, according to the company.

“How many [people] will have a dedicated charging facility at home is the single biggest challenge,” says Som Kapoor, partner for automotives at EY.

India’s electric vehicle manufacturers have been bedeviled by supply-chain problems. The sector is hugely dependent on imports, mostly from China, for parts such as battery packs and power cells.

Ola says it will import fuel cells from South Korea, but manufacture its own battery pack and motor, and produce the core components for its electric scooters at the company’s integrated Future Factory in Tamil Nadu. Aggarwal says the company will bring cell manufacturing to India within two years.

For India’s electric two-wheeler manufacturers, the road ahead may be strewn with rocks and potholes. Ola will have to negotiate those initial bumps successfully before it hits cruising speed.

“Once the total cost of ownership [of an electric two-wheeler] becomes lower than a vehicle with a conventional fuel engine, then there will be a geometrical progression,” says EY’s Kapoor. “The only thing is we don’t know when that will happen. It’s probably a billion-dollar question.”