A calendar
A day-long fast kept by married women in North India for their husbands' wellbeing, broken only once the moon is sighted through a sieve.
Sargi — a pre-dawn meal of fruit, nuts and sweets, usually given by a mother-in-law to her daughter-in-law — is eaten before the sun rises and the fast begins.
No food, no water, from sunrise. In many homes the day goes on as normal around the fast — work, errands, children — just without eating or drinking.
Women gather, often in a circle, for the puja: a small lamp, red thread, and the Karva Chauth katha told aloud — the story that explains the day.
The moon is sighted through a sieve, then the husband's face is seen the same way. Water is offered to the moon before anything is eaten.
The husband offers his wife the first bite or sip, by hand. The fast — and the day — ends there, together.
Married women fast without food or water from sunrise to moonrise, for their husbands' long life and wellbeing — a devotion carried by stories told at the evening puja. For many it is simply what the day is, regardless of the story behind it. Increasingly, husbands fast too. Anyone pregnant, diabetic, or unwell should check with a doctor before fasting.
If you're invited to the evening puja: dress modestly, in colour if you can, and don't offer a fasting woman food or water before moonrise. Let her family lead the rituals.