Approx. distance from the area to the city centre is kilometers.

Total number of environmental risks was in 20.
OR approx. distance from the area to the nearest risk was kilometers in 20.

from which environmental risks by type of risk
Total number of industry detrimental to health was in 20.
Total polluted land area was in 20.
Total number of traffic accidents was in 20.
Total number of other environmental risks (what) was in 20.

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