Fix grammar in the sentence: If the petrol has a low prices, countries will demands it more and that will produce bad consecuenses to our planets bit if the prices through petrol increase that might be a possibility to stop the demands of petrol, and a opportunity to start thinking about using other kind of natural resources (that does not cause so much damage to our planet, such as pollution) to replace the use into petrol.
If petrol has a low price, countries will demand more of it and that will produce bad consequences for our planet but if the price of petrol increases that might be an opportunity to stop the demand for petrol, and an opportunity to start thinking about using other kinds of natural resources (that do not cause so much damage to our planet, such as pollution) to replace the use of petrol.