Read the given passage and answer the questions that follow.

Pollution befouls the air and poisons water. Pollution induces the release of toxicants into the biosphere which makes the air unsuitable for breathing, harms the quality of water and soil, and causes the emission of substances that may cause damage to humans, plants and animals.
To cater to the needs of an increasing population, agriculture has been intensified through the use of a wide spectrum of fertilizers and pesticides. Diverse industries have been set up to produce chemicals including those that pose a danger to all life forms.

Rapid industrialisation has led to deterioration in the quality of air. Widespread use of coal and fossil fuels in industries and petroleum fuel in motor vehicles has aggravated the air pollution problem. Our atmosphere seems to have become a waste basket into which dust, noxious fumes, toxic gases and other pollutants are callously thrown.

The intensity of air pollution in Indian cities is increasing primarily due to our vintage vehicles and their poor performance. Water pollution, too has increased with the growth of our population and also that of our industries. Water pollution has acquired dangerous dimensions ever since sewage and industrial effluents have started being disposed of into the rivers.

Once considered sacred, the rivers are now turning murky and stink. It is sad that almost three-fourths of our fellow citizens have no choice but to drink filthy water. The severely polluted rivers due to mindless dumping of sewage and industrial wastes are a cause for concern not only to us humans but also to myriads of life forms that exist in water.

On the French and Italian rivier as we can no longer see the sparkling blue waters. The Mediterranean Sea is reported to be turning grey. Rivers and canals pour sewage, detergents and industrial waste into the sea; tankers flush their contents near the river or sea; bottles, rotting garbage and oil slicks are washed into the beaches. The phosphates and nitrates applied to farmlands as inorganic fertilizers, concentrate in lakes and estuaries causing algal blooms due to which wide expanses of water get choked, plants rot, oxygen is used up and fish die.

Q:

Since when has water pollution acquired dangerous dimensions?

• 1
  Since sacred rivers became murky and lost their sanctity
• 2
  Since sewage and industrial effluents started being disposed of in rivers
• 3
  Since the Mediterranean Sea started changing colour
• 4
  Since oil slicks started being washed on the shores of beaches