Though the world's worst civil nuclear accident happened in Ukraine, its biggest victim was arguably neighboring Belarus.
Given the prevailing winds, some 70 percent of Chornobyl's radioactive fallout landed on Belarus, contaminating one-third of its territory. One and a half million people -- including 420,000 children -- were located in the polluted area.
Valery Karbalevich of Strategy, a political-analysis center in Minsk, says the anniversary of the disaster is becoming routine: President Alyaksandr Lukashenka visits the affected regions, while the opposition remembers the disaster and uses the occasion to criticize the government.
"Today, the opposition invited people to go to the building of the presidential administration and leave petitions with proposals and demands there. After that, people are invited to gather in another location on the outskirts of the town where a mourning celebration is due to take place," Karbalevich says.
The Chornobyl anniversary has taken on great political significance in Belarus. Because the disaster was covered up for days after it happened, it came to be seen as a symbol of Soviet mendacity, and later became a traditional day for rallies by the opposition.
On 29 April, however, the Belarusian opposition will not demonstrate -- a fact Karbalevich says indicates that the memory of the public disaster is slowly fading.
However, Karbalevich says the tragedy remains a huge economic, social, political and ethic problem for Belarus.
"The problem is not gone, it remains," Karbalevich says. "All negative consequences have not disappeared. It is possible to say that the problems are growing but the public is paying less attention to it. The state also is paying less attention."
Karbalevich says that recently, the government floated the idea of building a nuclear plant to become more independent from Russian gas supplies. This kind of discussion was impossible several years ago.
Early on 26 April 1986, a fire broke out in Chornobyl's Unit Four reactor, and huge quantities of radioactive debris were released. The blast itself killed 31 people.
Concerned about the public-relations fallout, authorities initially covered up the news and neglected the surrounding population, which for four days had little if any information about the catastrophe.
After the government finally acknowledged the scale of the disaster, close to 150,000 inhabitants from nearby cities and villages were evacuated. People in Pripiat, the largest Ukrainian city in the region, believed they would return shortly. They never did.
Igor Losev, a professor at Kyiv's Mohyla Academy, says the disaster is being commemorated in Ukraine with meetings, rallies and other public events.
"It is business as usual, with the usual array of events -- conferences, rallies, meetings to commemorate this tragic anniversary," Losev says. "Everything goes on as usual. There is nothing principally new."
Losev says that though the celebrations are formal, the problem is real: "It [the disaster] concerns everybody and the consequences will be felt for a long time. Even today there are problems are there. There are hundreds of tons of nuclear fuel there and nobody knows what to do with it. And nobody can tell for sure what process is going on there in the building of former Chornobyl power station, where this notorious reactor was based, the one which exploded."
Losev and others have questioned the reliability of the so-called sarcophagus or covering that was placed over the damaged reactor. He says this problem is more than a Ukrainian concern because if something happens the whole region would again be affected.
The World Health Organization says there has been a large increase in radiation-related thyroid cancer among children in the affected areas. It estimates that 5 million people were exposed to radiation in Ukraine, Belarus, and Russia.
But the exact number of resulting deaths has been hard to pin down, also because cancer can take years to develop in people exposed to radiation.
And today, the International Federation of Red Cross and Red Crescent Societies said a program to detect thyroid cancer in contaminated areas is at risk due to dwindling donor funds -- just as cancer rates are rising.
Experts forecast the thyroid cancer rate would peak between 2006 and 2020.