Many Muslims think it is an unpardonable sin to neglect Ramadan, which comes once in a lunar calendar year.

Devout Muslims practise sawm (fasting) -- known as roza in India -- during this month. This means they may not eat or drink anything, including water, while the sun shines. In the evening, they eat small meals and visit friends and family.

A Bangladeshi Muslim sells caps on a street near Dhaka's national mosque, Baitul Mukarram. Muslims are expected to cover their heads when they pray in a mosque. Thousands of street vendors come to Dhaka during the month of Ramadan and do excellent business.

Photograph: Farjana K Godhuly/AFP/Getty Images