In which way humans have disturbed the balance of nature?

Not every much. Less than you would probably think. The major disturbances are mostly from pollution and deforestation.

we have desroyed many natural features, we have polluted a lot of the air (especially in urban areas)!!!

The earth has had several "great extinction events" including the one which wiped out the dinosaurs. There is strong evidence to believe we are currently experiencing a "great extinction event" and the cause of this one is not a meteor or supervolcano but the human race.

Our Polluted Planet
Brazil: “People who live [in Cubatão] call it ‘The Valley of Death.’ . . . The trees and soil are lifeless and, in increasing numbers, children are born dead or dying. What is alive is pollution.”—Latin America Daily Post.
China: “Most northeastern Chinese cities [suffer] from air pollution so pervasive that by late afternoon only hardened locals can walk the streets without burning lungs and watering eyes.”—Time.
Denmark: “Only a series of cold, windy summers with frequent northwesterly storms can save the Danish coast from an ecological catastrophe. . . . [In one area, because of the] lack of oxygen, fish and sea life will be unable to survive.”—Basler Zeitung.
Federal Republic of Germany: “A poisonous mixture spilled into the Rhine [from a chemical warehouse fire near Basel, Switzerland], destroying 15 years of Rhine rehabilitation [and tons of fish]. . . . The Sandoz accident has caused serious ecological damage to 280 kilometers [170 mi] of the Rhine.”—Der Spiegel.
Soviet Union: “The reactor disaster in Chernobyl . . . was a turning point in the history of modern civilization. And it was a catastrophe that will substantially affect us for centuries. . . . That 570 million Europeans, in varying degrees, were, are, and will continue to be exposed to supplemental radioactivity for 300 years will have unforeseeable consequences.”—Psychologie Heute.
United States: “Scientists . . . [have] voiced new concerns that acid rain, in addition to killing lakes, has stunted forest growth and possibly posed a health hazard to humans by contaminating drinking water.”—Maclean’s. These are just a few.
When God created humans, he instructed them to care for the earth. (Genesis 1:28; 2:15) Instead, in ignorance and in arrogance, they have polluted it. But the Creator has promised “to bring to ruin those ruining the earth.” Once willful polluters of the earth have been brought to ruin by God’s Kingdom government, the causes of pollution can be eliminated.—Revelation 11:18.
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