1. Although, from the viewpoint of long-term sustainability, groundwater development should be consistent with the availability of the resource in different regions, the analysis suggest uneven patterns of development in this respect. However, at the level of aggregation chosen, north-western India emerges as a serious case of overdevelopment of the resource; north-west Bangladesh has a large resource base that is intensively used; elsewhere in eastern South Asia, there seems to be room for carefully planned development. 2. At the sub-continental scale, the IWMI-Tata survey found that 55% of irrigated areas in the sample villages are under ‘pure groundwater irrigation’; this figure increases to 75% if conjunctive use areas are added. Pure canal irrigation serves only 14.5% of irrigated areas in sample villages, and ‘other sources’ account for less than 5%. In India, groundwater contribution is higher at 76% of irrigated areas in the sample villages; with conjunctive use, this ratio rises to 87% of irrigated areas. All these estimates suggest groundwater irrigation to have acquired greater quantitative significance than what is generally believed to be the case in the region. 3. In the South Asian context, terms like ‘rain-fed’ and ‘irrigated’ areas are meaningful only on the scale of parcels of farm holdings. Just around 5% of the villages surveyed counted themselves as totally rain-fed; in ‘tubewell dominated villages’, accounting for 42% of the total net cultivated area from all the surveyed villages, groundwater irrigation accounted for over 95% of irrigated area. However, even in canal dominated villages and conjunctive use villages, ‘pure tubewell irrigation’ accounted for 25 and 15% of the total irrigated area, respectively. 4. The preferred crops in groundwater dominated villages are coarse cereals, pulses, oilseeds, fibres and monsoon season (kharif or monsoon) paddy—all of which thrive under supplemental irrigation; wheat-rice rotation dominates conjunctive use and canal dominated villages. 5. Groundwater development is believed to be in some ways self-regulating; as groundwater use intensifies in a region, declining water tables raise the cost of pumping, placing a brake on further development. However, there is little sign that such self-regulating mechanisms have begun to work in the sub-continent, if continued growth of WEMs is any guide; if anything, the analysis suggests that the real intensification has only begun during the past decade. Around 50% of the WEMs covered by the survey were established after 1993, and there seems to be no indication of decline in the rate of the growth of WEMs, although the rate of the growth in total groundwater withdrawal may well be lower than the rate of the growth in the number of WEMs. 6. Energy pricing and supply policies have played a central role in shaping South Asia’s groundwater economy. At the sub-continental scale, a north–south energy divide was found with diesel pumps dominating the groundwater economy in the north, and electric WEMs dominating it in the south. 7. The analysis lends macro-level support to the hypothesis from micro-level research that the diesel pump is the mainstay of the poor and that the electricity subsidies provided in India are cornered primarily by the better off, since the average owner of the electric WEM has a larger, less fragmented land holding; and this gap becomes particularly sharp in all of India except the eastern region which has suffered progressive rural de-electrification. 8. There is also some support to the hypothesis that energy pricing and supply policies have a significant impact on the farmers’ choice of electricity or diesel as the source of motive power, and also on their use of pumps. In Pakistan Punjab and Sindh as well as in Bangladesh, where electricity is metered and commercially priced, diesel and electric pumps are evenly balanced. In eastern India and Nepal Terai, where ‘effective electricity subsidies’ are zero or negative, diesel pumps have increased rapidly as a proportion of the total WEMs in use. In the rest of India, electric WEMs have been growing steadily since the 1970s in response to significant ‘effective electricity subsidies’ available to farmers. Electric WEMs everywhere are operated for longer hours per year as well as per hectare compared to diesel WEMs. 9. Do electricity subsidies also result in a higher use of energy and water per hectare? The survey offers indications that they do. For kharif paddy and winter wheat, the average hours of pumping per hectare are far higher for electric WEM owners in western and southern India compared to diesel WEM owners there, or all groundwater irrigators elsewhere. 10. On the sub-continental scale, however, no single factor has played as dominant a role in creating new irrigation as the diesel pump. In a regression model that relates the net irrigated area to the number of diesel and electric WEMs, and the presence of canal, river, tanks/ponds in 278 villages, it was found that the impact of diesel WEMs is twice that of electric WEMs and 3.5 times higher than canals in explaining variations in the net irrigated area across sample villages. 11. Claims that groundwater accounts for 60% of India’s irrigated area are often contested on the ground that even if we take 200 km3 as the annual groundwater draft for irrigation, it can barely meet the crop water requirement of 25–30 million ha of land at 6,500–8,000 m3 of E-T per hectare of field crop, especially because India has large areas cultivated with rice which uses 10–12,000 m3 of water/ha consumptively. The survey results show that tubewell irrigation in most parts of South Asia is supplemental irrigation; that the average groundwater use is at best 30–50% of the total E-T requirements of these crops. The farmers use tubewells to ‘leverage’ rainwater precipitation and soil moisture and seem to be effective in optimizing returns to irrigation. 12. The IWMI-Tata survey also throws light on the functioning of pump irrigation markets in South Asia. It shows that these have shrunk in terms of breadth as well as depth in much of western and southern India because of both the growing pump density and the declining groundwater availability per WEM; in contrast, pump irrigation markets are booming in eastern India, Nepal Terai and Bangladesh as well as in Pakistan Punjab. The analysis also estimates that some 5 million ha of land in South Asia are irrigated by purchased pump irrigation. These results, however, are at variance with some other large-scale surveys published recently (Mukherji 2005). 13. The veracity of the popular hypothesis that South Asia’s water seller is a water lord who is ‘pumping groundwater for power and profit’ was tested. Whereas in specific situations this may well be correct, the subcontinental analysis shows that a typical water seller is a small landholder with fragmented land holdings who uses water selling to make the WEM viable. 14. While benefits of groundwater irrigation are widely recognized, there is growing concern about groundwater depletion and quality deterioration due to unregulated withdrawal. Finally, the survey tried to ascertain if farmers find water table decline, salinity, declining well yields as key problems facing them. The survey results suggested that by far the most important problems farmers perceive have to do with high energy costs of pumping and unreliable electricity supply. Falling water tables, salinity and others do figure, but are less critical than the energy cost and supply issues.