Why is thermal pollution a relative term

Thermal pollution means unwanted exhaust.it is defined as sudden increase or decrease in temperature of a natural body of water which may be ocean,lake,river or pond by human influence. Thermal pollution is a relative term because,roughly speaking,one person’s trash undesired pollution may be another person’s treasure. Example: this is normally occurs when a plant or facility takes in water from a natural resource and puts it back with an altered temperature.