Income tax on prize money from foreign country

My son won the Harvill Secker Young Translator's Prize of £1000 (translation of bengali short story in to english) in the 2018-19 financial year from United Kingdom. He received it in Rupees in india at his bank account. Will he have to pay Income Tax for it? How much? Please quote it rule. My son resides in india. He was 18 years old when he won the prize.