The Islamic holy month of Ramadan or Ramzan will begin on Thursday in India after the moon was sighted in New Delhi and Lucknow.
The start date is set by both lunar calculations and physical sightings which determine when the last day of one lunar month ends and a new one begins.
Traditionally, many Muslim-majority countries have followed the dates set by Saudi religious authorities, but in recent years many have used their own astronomical calculations.
Ramadan is a holy month for the world's nearly 1.5 billion Muslims, many of whom practise the ritual of dawn-to-dusk fasting and prayers.
The Ramadan fast, in which even water is prohibited, falls on especially long summer days this year for Muslims in the Northern Hemisphere.
Fasting is intended to bring the faithful closer to God and remind them of those less fortunate. It is also a chance to kick addictions like caffeine and cigarettes.
During the day, Muslims must abstain from eating, drinking, sex, gossip and cursing, and are encouraged to focus on meditative acts like prayer, reading the Quran and charity.
Tradition holds that it was during Ramadan that the Prophet Mohammed started receiving revelations of the Muslim holy book, the Koran.
Ramadan is one of the five "pillars" of Islam.
The others are the profession of faith ("there is no God but God and Mohammed is his messenger"), the obligation to pray five times a day, charity, and the pilgrimage to Mecca.
(With PTI Inputs)
