Statements: 1. It is the aim of the city's civic authority to get the air…

In a cause-and-effect item, one statement may describe a state or trend that plausibly explains the other - that statement is the cause, and the one it explains is its effect. Otherwise, the two statements are unrelated: either both function as causes with no link between them, or both function as effects that each arise from their own separate, unrelated cause. To decide, check whether one statement plausibly explains the other, or whether no such link exists.

Statement II reports a trend: asthma cases in the city are constantly increasing. Statement I reports a policy aim: the civic authority wants to cut air pollution by 20% within two months. A steady rise in asthma cases is a well-known health consequence of poor air quality, and such a public-health trend is exactly the kind of signal that would push a civic authority to set a pollution-reduction target. So the rising asthma cases in Statement II function as the cause, and the authority's pollution-reduction aim in Statement I is the effect - a policy response triggered by that trend.

Checking the other readings:

• Statement I producing Statement II would require the pollution-reduction aim itself to be driving up asthma cases, but an effort to cut air pollution is expected to lower respiratory illness over time, not raise it, so this direction of causation does not hold.

• Treating the two statements as independent causes would require the pollution-reduction aim and the asthma trend to be entirely unconnected, but both describe the same underlying air-quality issue, so they are not unrelated.

• Treating both statements as effects of independent causes would require Statement I and Statement II to each arise from their own separate, unrelated cause, with neither causing the other; but the direct plausible link between the rising asthma trend and the pollution-reduction aim means the two statements are not effects of two independent causes.

Hence, the rising asthma cases (Statement II) acting as the cause that drives the civic authority's pollution-reduction aim (Statement I) is the reading that holds.