World Aids Day is being observed around the world on 1 December, with people gathering to express support for those suffering from HIV/Aids, and to call for changes in treatment and social attitudes to the disease.

In India, where Aids still carries a strong social stigma, a group of HIV/Aids-affected children in Mumbai wore masks to disguise their identities. Many gatherings elsewhere lit commemorative candles arranged in the shape of the Aids red ribbon symbol.

Australia lit many major landmarks in red, and in Sydney the arrival of midnight on 30 November was marked with a display of fireworks over Sydney Opera House.

Started in 1988, World Aids Day is observed by all UN member states every year. The Global Steering Committee of the World Aids Campaign has selected the theme "Getting to Zero" for World Aids Day from 2011 until 2015. The idea behind the theme is to work for a reduction in new HIV infection, to end discrimination against those suffering with the disease, and to stop Aids-related deaths through prevention, testing, treatment and care.

The theme also aims to help provide anti-retroviral therapy (ART) to nearly 15 million people living with HIV by 2015.

AIDS since 1981

Since the first cases of HIV/Aids were reported in 1981, the incurable disease has claimed more than 25 million lives, according to the World Health Organisation (WHO).

The WHO figures suggest that approximately 34 million people were living with HIV in 2011. Sixty nine per cent of all these people are in Sub-Saharan Africa, which is the world's most affected region.

World AIDS Day in London

According to the official UK Website of World Aids Day, around 100,000 are currently living with HIV in the UK. Moreover, around 25,000 Britons are believed to be unaware they are infected with HIV.

London's G-A-Y Bar was celebrating by attempting to break its own Guinness World Record for having the most number of people tested for HIV at a single venue in eight hours. The bar  set the record last year at 467, according to an official release. For every person tested, G-A-Y Bar will donate £10 to the Elton John Aids Foundation.

A red ribbon sand sculpture created by Indian sand artist Sudarshan Patnaik on the eve of World AIDS Day, on a beach in the eastern Indian state of Odisha, 30 November, 2012
A red ribbon sand sculpture created by Indian sand artist Sudarshan Patnaik on the eve of World AIDS Day, on a beach in the eastern Indian state of Odisha, 30 November, 2012Reuters
An HIV-affected child in Mumbai wears a mask to protect his or her identity, as AIDS still carries a strong social stigma in India
An HIV-affected child in Mumbai wears a mask to protect his or her identity, as AIDS still carries a strong social stigma in IndiaReuters/Danish Siddiqui
Children suffering from HIV/AIDS form an AIDS ribbon as part of an AIDS awareness campaign to mark World AIDS Day in Mumbai, 1 December, 2012
Children suffering from HIV/AIDS form an AIDS ribbon as part of an AIDS awareness campaign to mark World AIDS Day in Mumbai, 1 December, 2012Reuters/Danish Siddiqui
Activists from a non-governmental organisation (NGO) light candles during an AIDS awareness campaign on the eve of World AIDS Day in Agartala, capital of India's northeastern state of Tripura, 30 November, 2012
Activists from a non-governmental organisation (NGO) light candles during an AIDS awareness campaign on the eve of World AIDS Day in Agartala, capital of India's northeastern state of Tripura, 30 November, 2012Reuters/Jayanta Dey
Fireworks explode over Sydney Opera House, 30 November, 2012, to mark World AIDS Day
Fireworks explode over Sydney Opera House, 30 November, 2012, to mark World AIDS DayReuters/Tim Wimborne
Candles arranged in the shape of an AIDS ribbon in Kiev, 29 November, 2012
Candles arranged in the shape of an AIDS ribbon in Kiev, 29 November, 2012Reuters/Anatolii Stepanov
Supporters of people living with HIV and AIDS light candles to form a ribbon, to mark World AIDS Day at Heroes Shrine in Quezon City, Metro Manila, 1 December, 2012
Supporters of people living with HIV and AIDS light candles to form a ribbon, to mark World AIDS Day at Heroes Shrine in Quezon City, Metro Manila, 1 December, 2012Reuters/Cheryl Ravelo
Supporters of people living with HIV and AIDS light candles to form a ribbon, to mark World AIDS Day at Heroes Shrine in Quezon City, Metro Manila, 1 December, 2012
Supporters of people living with HIV and AIDS light candles to form a ribbon, to mark World AIDS Day at Heroes Shrine in Quezon City, Metro Manila, 1 December, 2012Reuters/Cheryl Ravelo