Some of the few people who have seen the car describe a tiny, charming, four-door, five-seater hatchback shaped like a jelly bean, small in the front and broad in the back, the better to reduce wind resistance and permit a cheaper engine. “It’s a nice car  cute,” said A. K. Chaturvedi, senior vice president of business development at Lumax Industries, a supplier in Delhi that developed the car’s headlights and interior lamps.

Driving the cost-cutting were Tata’s engineers, who in an earlier project questioned whether their trucks really needed all four brake pads or could make do with three. As they built Tata’s new car, for about half the price of the next-cheapest Indian alternative, their guiding philosophy was: Do we really need that?

The model appearing on Thursday has no radio, no power steering, no power windows, no air-conditioning and one windshield wiper instead of two, according to suppliers and Tata’s own statements. Bucking prevailing habits, the car lacks a tachometer and uses an analog rather than digital speedometer, according to Mr. Taneja, who until recently was president of the Automotive Component Manufacturers Association of India, representing many of Tata’s suppliers as they signed deals with the company.

Frugal engineering pervades the car’s internal machinery, too, with even greater implications for the vehicle’s safety and longevity.

To save $10, Tata engineers redesigned the suspension to eliminate actuators in the headlights, the levelers that adjust the angle of the beam depending on how the car is loaded, according to Mr. Chaturvedi of Lumax. In lieu of the solid steel beam that typically connects steering wheels to axles, one supplier, Sona Koyo Steering Systems, used a hollow tube, said Kiran Deshmukh, the chief operating officer of the company, which is based in Delhi.

Tata chose wheel bearings that are strong enough to drive the car up to 45 miles an hour, but they will wear quickly above that speed, reducing the car’s life span but not threatening consumer safety, according to Mr. Taneja. The car’s top speed is 75 miles an hour.

Reducing the weight curbed material costs and enabled the company to use a cheaper engine. People familiar with the car describe a $700 rear-mounted engine built by the German company Bosch, measuring 600 to 660 cubic centimeters, with a horsepower in the range of 30 to 35. By comparison, the Honda Fit, one of the smallest cars available in the United States, has a horsepower of 109.