Every years during the Hindu month of Karthik, women across large parts of North India celebrate Karwa Chauth, fasting from sunrise to sunset to pray for the wellbeing of their husbands. And every year, the festival evokes heated debates on whether the ritual is sexist and regressive.

While other Hindu festivals like Navratri, Teej, Shiv Ratri, Janmashtami and Ram Navmi also involve ritual fasting, Karwa Chauth – which is being celebrated on Wednesday – receives the most flak: the ritual mandates that the married women in a house stay hungry, while their husbands eat specially prepared food.

According to Hindu mythology, the ritual began with princess Veeravati, who married a king. One day, she was tricked by her brothers into breaking the fast she held for her husband too early, as a result of which the king died.

As she rushed to her husband's side, Veeravati is supposed to have run into the goddess Parvati, and her consort Shiva, who told her fasting on Karwa Chauth would bring her dead husband back. The tale ended with Veeravati's husband returning from the afterlife.

Although there are several different rituals to break fasts during Karwa Chauth, the consistent and most Bollywood-friendly tradition involves women looking at their husbands through a sieve before taking their first sip of water to signal the end of their fast.

Of late, in an effort to break stereotypes surrounding the ritual, men have begun to fast for their wives on Karwa Chauth too. This isn't enough to mollify Karwa Chauth critics however, who ask – why fast at all? How can abstaining from food and water enhance a husband's life?

On Wednesday, celebrities took to Twitter to wish followers who were undertaking the fast. Some decided to use this opportunity to plug brands they endorsed.

This year, Twitter users also pointed out the true beneficiaries of the Karwa Chauth tradition – Bollywood, jewellery stores, and mehendi sellers.