• These days the increase in population creates great pressure on earth as well as its resources. 
• To satisfy the needs of ever growing population systematic mining, cutting of forests, building of forests and fields and roads took place all over the earth. 
• Burning of fossil fuels and release of enormous amounts of waste materials by industries contaminate air, water, and soil. 
• For providing food for the ever growing population, there is a need for increase in agricultural production. 
• Modern agriculture uses a large amount of chemical fertilizers and pesticides. 
• The most frightening aspect of pollution due to modern agriculture is the increase in the levels of toxins in our food.
• This increasingly proves to be very harmful not only to humans but also to all types of life on earth. 
• Since all living and non-living things on the earth are in one way or the other connected to each other, change affecting one, in due time affects all the others too. All these factors lead to ecological crisis.

Effects of ecological Grisis : 

1. If a particular species which feeds upon a particular kind of plant is exterminated, it would result in unchecked growth of that plant and it may intrude the area where other plants grow and disturb their growth. 

2. Many industries use chemicals and metals which flow into the rivers and streams. The metals like mercury are consumed by microorganisms in water and in turn beome the food of fishes. When human beings consume these fishes they too absorb some amount of mercury which is detrimental to their health. 

3. Farmers use Diclofenac to treat cattle; when the cattle die their flesh retains this chemical: When their flesh is consumed by vultures, diclofenac leads to kidney failure in them and they die.