New Delhi, Oct. 26 -- Emerging markets don't have a lot of those data centres, and it's not coming, trust me." So said World Bank president Ajay Banga in New York last month. Even where an emerging economy can arrange the land, water, power and fiscal space they demand, policymakers should ask whether hosting them is the best use of scarce resources, and whether the incentives on offer have been weighed against their costs.

The resources that data centres need are largely spoken for in most developing economies. Every unit of power committed to a data centre is a unit not available to a factory, an irrigation pump, or a household still making its way up the energy ladder. Finances are no less contested. Water is a third constraint: cooli...