Over $2 billion worth of payments from India to Russia for weapons systems have been stuck in limbo for around a year. New Delhi has been unable to use U.S. dollars due to fears about retaliatory sanctions from the West, and Moscow has refused to accept Indian rupees. This has India's air force the most, as it depends on a steady supply of Russian-made vehicles. This development, however, has not shifted Russia from being India's top supplier of weapons even though the purchases have slowed in the last few years due to sanctions.
But why is Russia the top supplier for India?
India has been a customer of Moscow since the 1960s during the Cold War. Their relationship was largely reliant on steady arms sales from the USSR to India, which was an important leader of the Non-Aligned Movement, and India was an important balance in the USSR & India vs. US, Pakistan, & China dynamic during much of the Cold War period. The USSR's disintegration at the end of the Cold War weakened its position, but Russian arms exports to India still remained a fundamental part of the two countries' relationship.
The damage done to the arms trade between India and Russia may or may not be permanent. If the West wants to seize the opportunity to draw India away from Russia (which may be made difficult due to India's massive increase in importing Russian oil), it must act now and expedite various programs, such as improving India's industrial base and building closer relations between New Delhi and Western capitals.