NEARLY ONE BILLION people are casting their votes in India’s general election. It is the biggest democratic exercise in history—and could also be the most expensive. Spending is expected to reach 1.35trn rupees ($16bn), according to the Centre for Media Studies (CMS), an Indian non-profit. That would be more than double the amount spent in the previous election in 2019 and even exceed the cash splashed in America’s presidential election in 2020. Why do Indian political parties spend such vast sums?

The explanation seems simple: the more voters there are, the more it costs parties to reach them. Yet the size of India’s electorate only partly explains the massive election bill. Over the past two decades, election spending has increased by 165% (after adjusting for inflation)—far more than the 27% rise in the population during the same period.