KALININGRAD, Russia (AP) — October Island was considered to some "a little corner of heaven" in the Russian city of Kaliningrad.

Then a World Cup stadium was built on the island.

Russia claims its World Cup stadiums meet the highest environmental standards, yet some have been built on top of ecologically sensitive areas. The site of the 35,000-seat Kaliningrad Stadium, where England and Spain will play, was one of Kaliningrad's last natural wetland sites, an island on the polluted Pregolya River. Its soft clay protected water-bird colonies from the port city's industrial development under first German, then Soviet, then Russian rule.

That changed in 2014 when more than a million tons of sand was spread on the site to stabilize it for the stadium construction.

Depending on your view, it's either a triumph of engineering or an environmental disaster.

"It was a typical delta island, with peat and a wetland reed-bed. It was a little corner of heaven in the city, where birds lived," said local ecologist Alexandra Korolyova. "Really, if Russia paid more attention to protecting the environment, it could potentially have become a reservation or national park within the city."

Korolyova campaigned against the stadium as part of local environmental organization Eco Defense because the island was "a filter" for the polluted river and "we've lost a lot and I don't see what we've gained."

The stadium, as with most of Russia's venues, is scheduled to become a hub for commercial and residential developments after the World Cup , and that could threaten the remaining wild parts of the island.

But there was another option.

At the design stage, then-Sports Minister Vitaly Mutko said the October Island wetland was too costly and challenging a site and pushed for a major rebuild of Kaliningrad's existing Baltika Stadium. Local officials successfully protested that the old stadium was a historic site, although efforts failed for a similarly historic stadium that was eventually rebuilt in the host city of Yekaterinburg.

The chairman of Russia's state-run World Cup organizing committee last week defended the choice of October Island.

"Everything was done in accordance with best practice," Arkady Dvorkovich said. "This place, in my view, was more like wasteland than a place with very good nature. Theoretically, of course, you can call any swamp a very beautiful and environmentally clean place, but it's not really correct in relation to the city infrastructure and the cities."

The Kaliningrad region Deputy Prime Minister Alexander Rolbinov dismissed environmental concerns.

"I don't remember any opposition from ecologists," he told the Associated Press, noting the key factor was the island's transport links to the rest of the city. "We've managed this task to an excellent standard, A-grade."

Other cities have environmental issues, too.

In Kazan, police detained seven environmental activists ahead of the Confederations Cup draw in 2016. They were campaigning against plans to expand a parking lot near the Kazan Arena by asphalting a riverside meadow home to rare species.

World Cup visitors in Moscow risk exacerbating the Russian capital's chronic problem disposing with garbage at overflowing landfills.

So much trash was dumped near the town of Volokolamsk, 110 kilometers (68 miles) west of Moscow, that a toxic mixture of hydrogen sulfide and methane gases enveloped the town during the winter. Residents complained of rashes and headaches and large protests were held in nine cities and towns in the Moscow region over pollution and government plans to build a garbage incinerator.

Public dismay with refuse disposal around the Russian capital increased sharply in March after scores of children in the town of Volokolamsk were sickened with symptoms of gas poisoning linked to a landfill.

Moscow students have also opposed the removal of rare trees near a World Cup fan zone.

Russia's smallest World Cup city, Saransk, leads the country in environmentally friendly trash disposal, with garbage being separated and recycled by a German company. Its stadium, which will host Portugal, was built on a mix of old housing and marshland.

The local minister in charge of World Cup preparations defended that decision.

"The whole district where the stadium stands and all the houses around it, literally six or seven years ago there was a marsh here," Alexei Merkushkin told the AP. "By putting all this territory in order, so to speak, we've already made a huge contribution to ecology because this was the most horrible place in the city ... I think the World Cup gave a huge boost to improving the environment in our city even though it was already very good."

___

Ellingworth reported from Saransk, Russia.