Millions of Indians celebrate Diwali, the festival of lights and one of the most important events in the Hindu calendar.

The annual festival usually falls between October and November, but the exact date varies each year as the Hindu calendar is based on the moon.

This year, Diwali will be celebrated on Thursday, but in some parts of the country the festival will be celebrated on Friday.

People light oil lamps and candles that day to symbolize the triumph of light over darkness and good over evil.

In the run-up to Diwali, people clean and organize their homes. New clothes are bought and sweets and gifts are exchanged with friends, family and neighbors.

Many draw traditional designs such as rangoli – made with colorful powders – outside their doors to welcome good luck and positivity.

On this day, families worship Lakshmi, the Hindu goddess of wealth.

Lamps are lit and windows and doors are left open to help the goddess find her way into people’s homes.

Fireworks are also a big part of the festivities, but in recent years several state governments have imposed restrictions or banned the practice as the northern Indian states struggle with severe air pollution.

There is a complete ban on the sale and use of fireworks in the capital Delhi during the festival, while states like Haryana, Punjab and Karnataka restrict the use of fireworks to specific hours on Diwali evening.