On this World AIDS Day, 30 years since the start of AIDS, we have reasons to be hopeful. Globally, the number of people becoming infected with HIV continues to fall, the number of AIDS-related deaths is dropping and the number of people receiving treatment has continued to grow. A total of 2.5 million deaths have been averted in low and middle-income countries since 1995.

In China, impressive progress has also been achieved: China's leaders have made AIDS a political priority and mobilized action. As a result, today over 110,000 people are receiving life-saving treatment in China and HIV testing and prevention services have been dramatically scaled up.

However, the job is not yet done. Despite good overall progress, the reality remains that only about two-fifths of people living with HIV have been tested and know their status; less than half of people needing AIDS treatment to survive are accessing it; and new HIV infections are growing at an alarming rate among men who have sex with men - with almost one in five men who have sex with men infected with HIV in some cities. For China to succeed in its AIDS response, there is a need to reach deeper, and more effectively, into communities of those most at risk – often those most marginalized and stigmatized within China's society.

Now is the time for action. China has set ambitious targets in its new Five-Year Plan (2011-15), specifically to reduce AIDS-related deaths by 30 percent, and new infections by 25 percent by 2015. China has also committed to achieving Millennium Development Goal 6: to halt and reverse the spread of HIV, by the same date.

Key to scaling up coverage of prevention and treatment services, and reaching these targets, is the elimination of discrimination.

Discrimination, and the fear of discrimination, make people reluctant to access life-saving HIV testing, prevention and treatment services. As a consequence, the epidemic continues to spread. In reducing discrimination, the government has a critical role to play.

Institutionalized discrimination, in hospitals, schools and workplaces, must not be tolerated, and must be challenged wherever it exists. Employment-related discrimination - one of the most harmful forms of institutional discrimination - needs urgent action, as people living with HIV continue to be denied jobs because of their HIV status; are fired if their status is revealed; or their career prospects are limited if they admit to living with HIV.

Fortunately, the Chinese government has shown strong commitment in the fight against discrimination: guidance from China's State Council, issued in 2010, instructs government departments at all levels to take steps to guarantee the rights of people living with HIV to freedom from discrimination and rights violations, and top-level state leaders have spoken out against discrimination. I am confident that through backing up these commitments with strong and concerted action, China will be able to build a more inclusive society, free of discrimination, and drive forward to achieve the vision of zero new infections, zero discrimination and zero AIDS-related deaths.

Mark Stirling is the UNAIDS Country Coordinator in Beijing