Air pollution is caused mainly by emissions from road vehicles, factories, power Stations, aircraft and the like and by the ‘large-scale burning of vegetation. It has long been recognized as an environmental problem, and as a source of costs to both industry and entire communities. Only relatively recently, however, has the full Significance of the impact of such pollution become apparent. and the global dominant, potentially disastrous, environmental problem facing humanity. Since the mid-eighteenth century, the burning of fossil fuels, deforestation, and other changes in land use have resulted in substantial increases in the concentration of carbon dioxide, ‘Methane, and nitrogen oxides in the atmosphere. By blocking the radiation back into space of much of the heat reaching the earth from the sun, these gases reduce Significantly the natural cooling - ‘effect of such radiation, thus creating a ‘greenhouse effect’ and causing a steady increase in temperatures on earth global warming. Although the Claim that: the earth’s atmosphere IS heating up has been disputed by some climatologists, the balance of scientific opinion is now firmly behind the hypothesis.
What is meant by radiation here?

An intellectual is one who is enlightened; and being an enlightened person, he has to give light to others who are in need of it. In every society, we find intellectuals such as philosophers, scientists, scholars, writers, and critics; and they, as enlightened men, have a great responsibility towards society. In a society, all cannot be intellectuals. If a time comes when all are intellectuals it would be a blessed time indeed; but intellectuals have the great responsibility of guiding others on to the right path. If today we have our civilisation and culture, if we have orders and security in life, and if our life is better that that of our primitive ancestors, it is because the intellectuals, from time to time, have been guiding humanity on the path of felicity and amity. Therefore, the intellectual should come out of his ivory tower and try to elevate others to his level."

What does the phrase 'ivory tower' in the extract denote?

An intellectual is one who is enlightened; and being an enlightened person, he has to give light to others who are in need of it. In every society, we find intellectuals such as philosophers, scientists, scholars, writers, and critics; and they, as enlightened men, have a great responsibility towards society. In a society, all cannot be intellectuals. If a time comes when all are intellectuals it would be a blessed time indeed; but intellectuals have the great responsibility of guiding others on to the right path. If today we have our civilisation and culture, if we have orders and security in life, and if our life is better that that of our primitive ancestors, it is because the intellectuals, from time to time, have been guiding humanity on the path of felicity and amity. Therefore, the intellectual should come out of his ivory tower and try to elevate others to his level."

Who are intellectuals according to the extract?

According to the passage, viruses can ———.

Leadership should be among those who have no axe to grind. People should have leaders with straigthforwardness, clear conception, felling for the poor and above all, with patriotism and statesmanlike foresight. It is essential that the decision taken by the leaders must be for the interest of the majority of people. They must understand the political, economic and social conditions of the country and should never hesitate to take any stern action against any wrong. come what may. they should see that unpatriotic and anti- social elements do not get the upper hand. It is by the integrity that the leaders of a country shall be judged from time to time, not by their speeches only.

The phrase 'have no axe to grind' means-