Children are the future custodians of natural resources. As adults, they will formulate and implement various social and business policies that will impact the planet. Hence, it is important that they are well-informed about environmental issues. The present study attempts to assess the level of environmental knowledge of Grade 9 (14-15 years old) school students in Delhi National Capital Region (NCR). The results indicate that, overall, adolescents have an average score in environmental knowledge. Children in private-run schools score higher than children in government-run schools. Gender does not have a significant relationship with environmental knowledge of the children. Father's education level has a significant relationship with children's environmental knowledge but the same does not hold good for the mother's education level. The overall participation of adolescents in environmental activities is low. Newspapers and school teachers are the top sources of environmental information for the school children followed closely by TV and internet. These findings have significance for environmental educators, school administration and environmental education policy implementers.