A subsidiary of India's largest industrial conglomerate has acquired four modest Washington hotels for $21.1 million as part of its plans to expand into the American market.

Tata is an Indian industrial giant with vast holdings ranging from steel production and truck manufacturing to a chain of 15 hotels in India that successfully cater to Western business people and tourists. It bought three of the hotels outright: the Canterbury House, 1733 N St. NW.; Hampshire Hotel, 1310 New Hampshire Ave. NW; and the Quality Inn at 1315 16th St. NW.

The Indian group also took over the lease on the Ramada Inn Central at 1430 Rhode Island Avenue NW, a company spokesman said. The hotels contain a total of nearly 1,000 rooms.

Tata, trading under the name of Jana Corp., bought the hotels from four different partnerships of lawyers headed by attorney Daniel A. Honig and received a $20 million mortgage from Hong Kong & Shanghai Banking Corp. of New York, according to the Lusk Report, a weekly report of local real estate transactions.

"We have been eyeing the Washington market for quite sometime," said Deepak Panjabi, vice president for administration for Taj International Hotels, Tata's American hotel subsidiary. "We thought it would have good potential."

The four hotels are located in fringe areas outside the popular hotel districts of downtown and Georgetown.

"We buy properties that we can upgrade," said a company spokesman in New York. "They lend themselves to be upgraded into first-class hotels" because the four contain mainly suites rather than single rooms. They were formerly apartment buildings, the spokesman said.

Tata, which has been operating hotels in India since the turn of the century, has as its flagship the grand, palatial-looking Taj Mahal Inter-Continental, which overlooks the harbor in Bombay.

The company operates hotels in India and the Middle East through its hotel subsidiary and began expanding into Western Europe two years ago when it purchased two London hotels, the 456-room St. James Hotel and 160-room Bailey's Hotel.

Tata's first American purchase came in September 1981, when it bought the 750-room Lexington Hotel in New York City.

Tata, an Indian industrial house which had its beginning in the last century, now has assets in excess of $2 billion and sales of more than $3 billion, a company spokesman said.

A spokesperson for Honig said that the attorney and a partnership of other attorneys started buying the hotels six to eight years ago. "He sold because he got a good offer," the spokesperson said.