What concentration of carboxyhaemoglobin complex in the human body reduces the oxygen-carrying capacity of haemoglobin?

How is electricity produced in a thermal power station?

Mention the harmful effect of ultra violet radiations.

What is meant by environmental pollution?

State whether the following statements are true or false:
$(1)$ Mist is produced by particles of spread liquid and by condensation of vapour in air.
$(2)$ Particulate matter of size up to $5 \ \mu m$ reaches directly into the lungs.
$(3)$ Ozone and nitric oxide cause irritation in the nose and throat.

How is excessive content of $CO_2$ responsible for global warming?