It is a common practice to undertake desilting of the overhead water tanks. What is the possible source of silt that gets deposited in the water tanks?
The source of silt that get deposited in overhead water tank are soil particles, which are carried out with water from the source of supply like deep borewell, rivers, etc.
What is cultural eutrophication?
The phenomenon wherein effluents from the industries and homes accelerate the natural and cultural ageing process of lakes and other water bodies that normally may take thousands of years is called accelerated eutrophication.
List any two adverse effects of particulate matter on human health.
The fine particulate (PM of size 2.5 œm or less) can problems cause
(i) Breathing and respiratory
(ii) Irritation
(iii) Inflammations
(iv) Damage to the lungs and premature death
What is the raw material for polyblend?
Polyblends are natural man made fibres, made by the mixture of two or more polymers especially plastic waste products
Blends of polyblend and bitumen, when used, help to increase road life by a factor of three. What is the reason?
Polyblend is a fine powder of recycled modified plastic. The binding property of plastic makes the road last longer besides giving added strength to withstand more loads.
This is because
(i) Plastic increases the melting point of the bitumen which would prevent it from melting in India's hot and extremely humid climate, where temperature frequently cross $50^{\circ} \mathrm{C}$.
(ii) Rainwater will not seep through because of the plastic in the tar.