The problem: Answer a question about this article:
By the 1990s Mexico City had become infamous as one of the world's most polluted cities; however the city has become a model for dramatically lowering pollution levels. By 2014 carbon monoxide pollution had dropped dramatically, while levels of sulfur dioxide and nitrogen dioxide were nearly three times lower than in 1992. The levels of signature pollutants in Mexico City are similar to those of Los Angeles.[citation needed] Despite the cleanup, the metropolitan area is still the most ozone-polluted part of the country, with ozone levels 2.5 times beyond WHO-defined safe limits.
Who decides safe levels of o-zone in cities?
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The answer: WHO

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Saint Helena was first settled by the English in 1659, and the island has a population of about 4,250 inhabitants, mainly descended from people from Britain settlers ("planters") and soldiers and slaves who were brought there from the beginning of settlement initially from Africa (the Cape Verde Islands, Gold Coast and west coast of Africa are mentioned in early records), then India and Madagascar. Eventually the planters felt there were too many slaves and no more were imported after 1792.
Which year did the inhabitants decide there were too many slaves?
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The answer: 1792

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Somerton took over from Ilchester as the county town in the late thirteenth century, but it declined in importance and the status of county town transferred to Taunton about 1366. The county has two cities, Bath and Wells, and 30 towns (including the county town of Taunton, which has no town council but instead is the chief settlement of the county's only borough). The largest urban areas in terms of population are Bath, Weston-super-Mare, Taunton, Yeovil and Bridgwater. Many settlements developed because of their strategic importance in relation to geographical features, such as river crossings or valleys in ranges of hills. Examples include Axbridge on the River Axe, Castle Cary on the River Cary, North Petherton on the River Parrett, and Ilminster, where there was a crossing point on the River Isle. Midsomer Norton lies on the River Somer; while the Wellow Brook and the Fosse Way Roman road run through Radstock. Chard is the most southerly town in Somerset, and at an altitude of 121 m (397 ft) it is also the highest.
How many cities and towns in Somerset
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The answer: The county has two cities, Bath and Wells, and 30 towns

The problem: Answer a question about this article:
Hunting along migration routes threatens some bird species. The populations of Siberian cranes (Leucogeranus leucogeranus) that wintered in India declined due to hunting along the route, particularly in Afghanistan and Central Asia. Birds were last seen in their favourite wintering grounds in Keoladeo National Park in 2002. Structures such as power lines, wind farms and offshore oil-rigs have also been known to affect migratory birds. Other migration hazards include pollution, storms, wildfires, and habitat destruction along migration routes, denying migrants food at stopover points. For example, in the East AsianAustralasian Flyway, up to 65% of key intertidal habitat at the Yellow Sea migration bottleneck has been destroyed since the 1950s.
What threatens some bird species?
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The answer:
Hunting along migration routes