The analysis of sectoral growth in GSDP of Delhi at constant prices reveals that the contribution of primary sector comprising of agriculture, livestock, forestry, fishing, mining & quarrying and also the secondary sector comprising of manufacturing, electricity, gas, water supply and construction is decreasing. At the same time, the tertiary sector, also called the service sector comprising of trade, hotels and restaurants, transport, storage, communication, financing & insurance, real estate, business services, public administration, is a major contributor in the economy of Delhi and getting enhanced regularly. The contribution of primary sector which was 3.85% during 1993-94 has come down to 0.97% in 2004-05 at 1993-94 constant prices. Similarly the contribution of secondary sector recorded at 25.20% in 1993-94, has also declined to 19.92% in 2004-05. On the other hand, the contribution of tertiary sector worked out to 70.95% in 1993-94 has enhanced to 79.11% in 2004-05.

The reasons for change in the sectoral composition of Delhi economy could be attributed to the rapid urbanisation and consequential reduction in agricultural and allied activities on one hand and substantial increase in activities pertaining to the services sector on the other. At the same time, regular monitoring of environmental degradation by different government agencies on the directives of Supreme Court and subsequent closing of polluting industrial units in and around Delhi also contributed to the reduction of output in the secondary sector.