A thousand aircraft flew in formation in the night skies above the capital New Delhi, flashing the saffron, white and green of the national flag, before rearranging themselves into a silhouette of independence hero Mahatma Gandhi.

The light show closed a series of extravagant sunset troop manoeuvres for India's Beating Retreat, a music-filled drill ceremony for soldiers returning to base that has its origins in 17th-century British military tradition.

It is staged each year three days after the country's annual celebrations to mark the anniversary of India's 1950 republican constitution.

The event has special significance this year as the nation of 1.4 billion people prepares to mark 75 years since the end of British colonial rule in August.

This year's Beating Retreat sparked a minor local controversy over the decision by Prime Minister Narendra Modi's Hindu nationalist government to drop the Christian hymn "Abide With Me" from the ceremony's featured songs.

The hymn, said to be a favourite of the London-educated Gandhi, was dropped because it was a sign of the country's colonial past, media reports said, quoting government sources.

The song had been a permanent fixture of the ceremony since 1950.

It has been replaced by a patriotic song dedicated to Indian soldiers who died in a brief border war with China in 1962.