Sources and historical deposition of polycyclic aromatic hydrocarbons (PAHs) were investigated in dated sediment cores from Lakes Nainital and Bhimtal in the Kumaun Himalaya The data show that PAH deposition has increased in recent years and is associated with an increase in anthropogenic activity. The lake sediments dominantly contain low molecular weight (LMW) PAHs. derived mainly from petrogenic sources Concentrations of individual and total PAHs were categorized on the basis of sediment quality criteria. According to this, the pollutants pose a potential threat to aquatic life.