Temperature usually decreases with an increase in altitude sometimes the reverse is true . Generally the temperature inversion means increase of temperature with altitude . inversions are usually confind to fairly shallow layers and may occure near to the surface or at higher altitude . they acts as a lid for weather and pollutants . visibility is often restricted due to fog , haze , smoke and low clouds . temperature inversions occure in stable air with little or no wind and turbulence . one of the most familiar types of inversion is the one that forms just above the ground on cool , clear nights . as the ground surface cools it lowers the adjacent air temperature . if this process continues the air within a few houndred feet above surface may become even cooler than the air above it . an inversion can also occure when cool air is forced under warm air or when warm air spreads over cold both of these are known as frontal inversion .