Every year, Muslims across the globe observe a month of daily fasting during Ramadan.
The ninth month of the Islamic calendar involves abstaining from food, drink, smoking and sex between early morning and sunset.
Fasting - during Ramadan or for other reasons - is one of the Five Pillars of Islam, the others being faith, prayer, charity and the pilgrimage to Mecca.
Ramadan 2019 was a test of faith because it fell in the longer days of summer, meaning extended hours of going without food and drink in hot weather.
Ramadan 2020 was during a full lockdown in the UK and across the world so that presented another set of challenges, with Muslims told to remain in their own homes, despite the usual tradition for communal meals and prayers.
For 2021, there are still restrictions in place but mosques are open for limited, pre-booked communal worship and special guidance has been issued on night prayers, meals before and after fasting, and spiritual retreats.
This is the month in which the Qur'an was revealed to the prophet Muhammad and so it's regarded as a time filled with blessings when worshippers focus their minds and bodies on spirituality rather than on earthly needs and indulgences.
It's traditional to convey greetings and blessings to those who are about to begin an entire month of fasting.
So what are the typical blessings to be said to Muslim family and friends at the start of the month? How do you wish people a Happy Ramadan?
And once the month of fasting is over, it's time to celebrate Eid al-Fitr and wish each other Eid Mubarak.
With strict rules around Ramadan, there have been concerns from some people about whether they can have their Covid-19 vaccine injection when they are fasting.
The British Islamic Medical Association (BIMA) has consulted a wide range of scholars and the opinion of the vast majority is that receiving a vaccine by injection does not invalidate the fast.
It said: “Taking the Covid-19 vaccines currently licensed in the UK does not invalidate the fast.” People are also advised to get tested regularly, have their vaccine as soon as they can, and continue to follow Hands, Face, Space and Fresh Air guidance.
The BIMA also considered whether Muslims should take Covid-19 tests during Ramadan and said: “Taking the Covid-19 PCR or lateral flow tests does not invalidate the fast during Ramadan, as per the opinion of the majority of Islamic scholars.”