India today "deplored" the loss of lives in the South Korean air crash a week ago, but the late and relatively mild statement appeared to fuel criticism of Prime Minister Indira Gandhi's response to the downing of the plane.

Although the statement expressed "shock," an official spokesman said the full facts of the incident had not yet been clearly established. He added, "We do not understand how the plane was so long off course, nor how it could not have been identified as a civilian aircraft."

The statement neither mentioned the Soviet Union by name, nor explicitly criticized it for shooting down the jetliner.

Western diplomatic sources here noted that the Indian foreign minister, P.V. Narasimha Rao, was in Moscow this week for talks with Soviet Foreign Minister Andrei Gromyko to discuss issues expected to come up at a U.N. General Assembly session to be addressed by Gandhi on Sept. 28, and that the low-key Indian reaction may have been linked to that visit.

Another factor is India's longstanding close relationship with the Soviets, who are its major arms supplier.

Today's official statement called upon the international community urgently to address itself to removing the causes of mistrust and confrontation between nations, saying that in such an atmosphere "there is always a risk of even an error leading to a calamity."

India's reaction had become a political issue for Gandhi's opponents before tonight's statement. Leaders of the opposition Janata Party called on her to "clearly and categorically" denounce what they termed an "act of barbarism" by the Soviet Union.

Subramaniam Swamy, deputy leader of the Janata Party in Parliament, said the United States had uncovered "impeccable evidence" that the downing of the civilian airliner was "a deliberate decision of the Soviet military command."

The United States has long been sensitive about India's ambivalent public posture on the 1979 Soviet occupation of Afghanistan.

Despite the low-key Indian response, most major daily newspapers here have editorially condemned the Soviet action, with The Times of India demanding an apology and compensation. The respected Hindustan Times today carried a satirical interview with an anonymous government "spokesman," headlined, "Pardon, Your Tilt is Showing."