Over the past decade, the Chinese government has consistently shown leadership at the highest levels in its national response to the AIDS epidemic. HIV funding has increased rapidly, more than quadrupling since 2003 to over 2 billion yuan ($309 million) in 2010. The country's most senior leaders, including President Hu Jintao and Premier Wen Jiabao, have met with people living with and affected by HIV on regular occasions, underscoring the commitment of the Chinese government to addressing HIV in China.

This commitment has yielded concrete results: a dramatic increase in the number of people receiving antiretroviral treatment, from about zero in 2003 to more than 86,000 in 2010, representing more than 40 percent coverage; a major roll-out of methadone maintenance treatment for people who inject drugs, with more than 700 clinics now providing life-saving treatment and prevention services to almost 300,000 people; and nationwide efforts to prevent new HIV infections in children. These are all important achievements that will slow the spread of HIV in China.

But areas of concern remain - perhaps foremost among these, a rapidly-expanding HIV epidemic among men who have sex with men (MSM). Approximately one in three new HIV infections in China is among MSM, and a majority of these infections occur in cities. To ensure a successful national AIDS response, urgent action is needed in metropolitan areas. HIV programs focused on MSM in cities will also help mitigate the impact of the epidemic in rural areas, as many city dwellers are migrants who return to their villages of origin on a regular basis.

First, HIV strategies must be based on local realities; they should be strategically targeted and backed up with budgetary funding. Despite their increased risk of HIV infection, less than half of the MSM population has access to HIV testing services. To expand coverage of HIV services for MSM, city authorities must work to strengthen demand among those most at risk by ensuring that HIV testing is quick, easy to use and administered confidentially.

Second, ensuring zero tolerance for discrimination is key to encouraging greater uptake of prevention and treatment services among MSM and must be at the core of response plans. A recent report by the International Labor Organization and China's Center for Disease Control found that people living with HIV face significant obstacles in gaining access to medical treatment in China and, in many cases, are refused treatment outright. These forms of institutional discrimination are unacceptable and undo much of the good work China has undertaken in recent years. It is important that steps be taken immediately to address these issues.

Third, community-based organizations (CBOs) play a critical role in strengthening demand for HIV services in cities, and they must be fully supported. In view of the stigma associated with homosexuality in China, MSM are often reluctant to risk exposing their identity, particularly those who are married with families. As a result, they often prefer to seek HIV prevention and treatment services from CBOs rather than from government-run health facilities.

Many CBOs are already operating in China's cities and achieving important results. However, if CBOs are to participate more effectively and sustainably in the AIDS response, they must be allowed to register legally and gain access to funding. This was recognized in the guidance issued last December by China's State Council, which called on relevant departments to facilitate the legal registration of social organizations - an important step forward for China's HIV response.

Cities are at the heart of China's development and progress and they must remain at the vanguard of its HIV response. Through bold action to address HIV among men who have sex with men, cities can lead the way in achieving the UNAIDS vision of zero new HIV infections, zero discrimination and zero AIDS-related deaths.

The author is executive director of UNAIDS and under secretary-general of the United Nations.