HONG KONG — Thousands of people marched through Hong Kong’s streets yesterday to demand the right to pick their city’s leader and legislature and hoisted yellow umbrellas to form the year 2012 — their target year for full democracy. The demonstrators chanted “One person, one vote, the only way to go” and “Universal suffrage in 2012” as they marched to government headquarters.

“We need to have a good political environment in order to sustain our economic development,” one of the participants, a 51-year-old businessman named Michael Hui, said.

The former British colony returned to Chinese rule in 1997 but was promised a wide degree of autonomy under a “one country, two systems” formula. Beijing has ruled out full democracy for the territory before 2008.

As it stands now, Hong Kong residents don’t have the right to vote for the territory’s leader, known as the chief executive. An 800-member election committee, considered partial to the Chinese government, makes the selection.

Only half of the local legislative assembly’s 60 lawmakers are also directly elected. The rest are picked by special interest groups, such as businesses and labor unions. Many Hong Kongers believe the city is ready for democratic reform, but Beijing loyalists — especially those in the business community — worry that political changes will create social upheaval and upset the economy.