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.