India is honouring Singapore's founding father Lee Kuan Yew by designating tomorrow as a day of national mourning.

Indian Prime Minister Narendra Modi is travelling to Singapore where he will join other foreign leaders for the state funeral.

In an unprecedented gesture, New Delhi announced yesterday that the Indian flag will be lowered to half-mast across the country tomorrow and there will be no official entertainment on the day.

It is unusual for India to honour a person who had retired from national leadership for nearly a quarter-century.