The chairman of China Evergrande Group has been placed under police surveillance, Bloomberg News reported on Wednesday, raising more doubts about the embattled developer's future as it grapples with mounting risks of liquidation.

Evergrande is the world's most indebted property developer and has been at the centre of an unprecedented liquidity crisis in China's property sector, which accounts for roughly a quarter of the world's second-largest economy.

Once China's top-selling developer, Evergrande's financial crisis became public in 2021 and since then it and a string of its peers have defaulted on their offshore debt obligations amid slowing home sales and fewer new avenues for fundraising, triggering fears of wider contagion that could spread to the country's banks.

Here is a timeline of how Evergrande's debt crisis has unfolded:

August, 2021

Many Evergrande projects across the country halt construction due to overdue payments.

China's central bank and banking watchdog summon senior executives and issue a rare warning that Evergrande must reduce its debt risks and prioritise stability.

September, 2021

It misses two offshore bond coupon payments totalling $131 million. The payments have a grace period of 30 days.

Evergrande engages financial advisers to examine options, warning of cross-default risks amid plunging property sales.

November, 2021

Hui sells 1.2 billion shares worth HK$2.68 billion ($342.7 million), lowering his stake in Evergrande to 67.9% from 77%.

March, 2022

Evergrande suspends trading in its shares, citing its inability to publish audited results before March 31, and an investigation of the property management arm in which 13.4 billion yuan of deposits were seized by banks.

November, 2022

A mansion belonging to Evergrande's chairman in Hong Kong's prestigious The Peak residential enclave is seized by lender China Construction Bank (Asia).

December, 2022

Evergrande says it has resumed work on 631 pre-sold and undelivered projects.

January, 2023

Evergrande says its then auditor PricewaterhouseCoopers resigned amid disagreements over matters relating to the audit of its 2021 accounts.

February, 2023

An independent committee finds Evergrande's directors fell "below standards" through their involvement in diverting loans secured by unit Evergrande Property Services to the group.

March, 2023

Evergrande announces plans for the restructuring of its offshore debt, giving creditors a basket of options to swap their debt into new bonds and equity-linked instruments backed by the group and its two Hong Kong-listed companies.

April, 2023

Evergrande says 77% of the holders of class-A debts and 30% of the holders of class-C debts have submitted their support for the restructuring proposal.

July, 2023

Evergrande posts a net loss of 476 billion yuan and 105.9 billion yuan for 2021 and 2022, respectively, versus a net profit of 8.1 billion yuan in 2020 when its operation was normal.

August, 2023

Evergrande says it plans to seek protection under Chapter 15 of the U.S. bankruptcy code, which shields non-U.S. companies that are undergoing restructurings from creditors that hope to sue them or tie up assets in the U.S.

Evergrande reports a 33 billion yuan loss in January-June, versus a 66.4 billion yuan loss in the same period last year.

Trading in Evergrande's shares resumes after 17 months, with 79% of its market value lost from when it was last traded.

September, 2023

China's National Administration of Financial Regulation approves the setup of a state-owned insurer to take over all of asset and liabilities of Evergrande Life Insurance, a 50%-owned investee company of Evergrande.

Police in southern China say they have detained some staff at Evergrande Financial Wealth Management, an indirect wholly-owned subsidiary of Evergrande.

Evergrande defers scheme meeting initially scheduled on Sept 25 and Sept 26, citing needs to reassess the terms of proposed restructuring.

Evergrande says it is unable to meet qualifications for the issuance of new notes as its flagship onshore unit Hengda Real Estate Group was being probed by the Chinese securities regulator for suspected violation of information disclosure.

A major group of offshore creditors of Evergrande plan to join a court petition to liquidate the developer, if it doesn't submit a new debt revamp plan by next month, Reuters reports, citing two sources familiar with the matter.

($1 = 7.8201 Hong Kong dollars)

(Reporting by Clare Jim and Xie Yu; Additional reporting by Roxanne Liu; Editing by Sumeet Chatterjee and Kim Coghill)