Every year around October and November, skies across the UK can be seen filled with fireworks as celebrations take place.

Diwali is a five-day “Festival of Lights” and a celebration of the triumph of good over evil, and it begins this week.

Here is an explainer on why it is celebrated and what takes place:

– When is it celebrated?

The festival usually occurs between October and November, with the date changing each year.

This year it will take place between November 2-6, with the most important day of the festival falling on November 4.

– Who celebrates it and why?

Originating in India, Diwali is celebrated across the world by Hindus, Sikhs and Jains, but for different reasons.

The Hindus celebrate the return of Lord Rama – an avatar of the Hindu supreme god Lord Vishnu- with his wife and brother to the Kingdom of Ayodhya after an exile of 14 years.

The streets and towns were lit up with Diwas (candles) to welcome them home.

In South India, Diwali is the day in which demon Narakasura was defeated by Sri Krishna and Satyabhama.

To others, Diwali is dedicated to the Goddess Lakshmi, who is believed to bring wealth and prosperity.

In many households, the celebrations include a puja (worship) of the Goddess to pray for health and happiness.

Sikhs, meanwhile, celebrate the release from prison of the sixth guru Hargobind Singh in 1619.

The Jains celebrate Diwali as Lord Mahavira, the last Jain Tirthankaras, achieved Nirvana.

According to the British Sikh Association, Diwali celebrations in UK cities have become probably the largest outside India.

A spokesman told the PA news agency: “Diwali is celebrated at the residence of the Prime Minister, 10 Downing Street, at the House of Commons, with cross-party Parliamentarians joining in the celebrations as we are today.

“Diwali at Trafalgar Square is attended by thousands of people, including tourists visiting the capital who are mesmerized to see the colourful pageant of music, dance and food.”

– What do people do?

According to the Hindu Council UK, Diwali is “probably best experienced in India”, though celebrations are seen widely across the globe.

A spokesman for the organisation said: “In London, in particular, Diwali has become a mega-event to celebrate the culture and traditions of India. From live music to dance shows and much more. London really goes for it.

“It’s a family friendly event with lots of activities going on including music and dance performances, workshops and some kids activities. And there’s a huge array of Indian food to sample from all the food stalls and a massive firework display to end the festival.

“In India, houses are cleaned, often renovated, and always illuminated with sparkling fairy lights and oil lamps. Most doorways and foyers are decorated with beautiful designs on the floor, called rangolis.

“Children wait at the sweet shops to buy sweets, excited youngsters light up the skies with their repertoire of carefully sourced firecrackers and shout ‘Happy Diwali’ to the unsuspecting passers-by.”

Gifts of clothes and sweets are also exchanged between people, with markets and stalls selling items months before the festival takes place.