Pollution

Pollution as a travel topic may refer to
 * Air pollution as a public health problem and nuisance affecting travellers
 * Air pollution as CO2 emissions, in the context of sustainable travel
 * Water pollution creating a hazard to travellers who may drink or bathe in contaminated water
 * Soil pollution (such as through the use of certain fertilizers) creating a hazard to travellers who may eat contaminated food
 * Light pollution as a concern to travellers who pursue astronomy