Events following Japan's worst quake and nuclear incident

Here is a brief timeline of events after the 9.0 magnitude quake, the biggest recorded in Japan's history:

March 11, 2011: A 9.0 magnitude quake hits off the coast of northeast Japan, triggering a tsunami that devastates towns and villages. The tsunami swamps backup power and cooling systems at Tokyo Electric Power Co's (TEPCO) Fukushima Daiichi nuclear plant, eventually causing meltdowns at three of six reactors. Two months later, TEPCO confirms meltdowns occurred.

Government declares a nuclear emergency and tells residents within a 3 km radius of the plant to evacuate. The evacuation zone is expanded in stages to a 20 km radius over the next two days. More than 160,000 people are eventually evacuated.

March 12: TEPCO begins injecting seawater to cool the reactors' fuel rods. People stock up on groceries and supplies in Tokyo, about 250 km away, amid radiation fears.

Naoto Kan, prime minister at the time, says later he feared he might have to evacuate Tokyo.

March 16: Emperor Akihito gives a rare televised address expressing deep worry about the crisis.

March 22: Technicians working at the plant attach power cables to all six reactors and start a pump at one to cool overheating nuclear fuel rods.

April 4: Engineers release over 10,000 tons of contaminated water - about 100 times more radioactive than legal limits - that had been used to cool overheated fuel rods after running out of storage capacity.

May 20: TEPCO's president, Masataka Shimizu, 66, resigns, taking responsibility for the nuclear crisis.

Aug. 26: Kan confirms he will resign.

Dec. 16: Japan declares damaged reactors are in a stable state of "cold shutdown".

July 1, 2012: Kansai Electric Power Co restarts the 1,180-megawatt No. 3 unit at its Ohi atomic plant, Japan's first nuclear reactor to come back online since the Fukushima crisis, despite public concerns about nuclear safety.

July 5, 2012: A commission appointed by parliament concludes Fukushima was a "profoundly man-made disaster" that could have been prevented, and mitigated by a more effective response.

Dec. 26, 2012: Shinzo Abe elected prime minister after his Liberal Democratic Party wins general election, ousting the Democratic Party of Japan, in power at the time of the crisis.

July 22, 2013: TEPCO admits that since the 2011 reactor breaches, radioactive water has continued to leak from the plant into groundwater, making it radioactive, with implications for drinking water and for the Pacific Ocean.

Sept. 7, 2013: In a bid led by Abe, Tokyo is declared the host of the 2020 Summer Olympic Games, with a promise of showcasing a reconstructed Fukushima. Abe says the crippled plant is "under control".

April 1, 2014: People begin to return to the 20-km exclusion zone around Fukushima as decontamination of the area is completed.

June 3, 2014: TEPCO begins work on an "ice wall" to slow the flow of ground water into the wrecked plant, but the buildup of contaminated water continues, slowing recovery efforts.

Nov. 5, 2014: TEPCO removes 400 tonnes of spent uranium fuel from a damaged reactor building, the first of four sets of used rods to be removed in a cleanup expected to last decades.

Feb. 7, 2018: TEPCO ordered to pay about 1.1 billion yen ($10 million) to 321 Fukushima residents for damages in a class action suit.

Sept. 5, 2018: Japan acknowledges for the first time that radiation at the Fukushima plant killed a worker there, ruling that compensation should be paid to the family of the man in his 50s who died of lung cancer.

Sept. 19, 2019: Former TEPCO chairman Tsunehisa Katsumata, and former executives Ichiro Takekuro and Sakae Muto cleared of criminal charges of professional negligence resulting in injury and death in the only criminal case to arise from the crisis.