After a six-year delay, India is finally set to count its population in a two-phase census that will conclude in 2027, the government has announced.

India's decennial census is one of the world's largest administrative exercises and provides critical data for planning welfare schemes, allocating federal funds, drawing electoral boundaries and making key policy decisions.

It was originally due in 2021, but has been delayed several times since. The last census was conducted in 2011.

Prime Minister Narendra Modi's government had initially cited the Covid-19 pandemic as the main reason but critics have questioned what has taken so long to resume the exercise.

On Wednesday, India's home ministry said in a statement that the much-awaited census will be conducted in two phases, with 1 March 2027 as the reference date.

For the snow-bound Himalayan regions, which includes the states of Uttarakhand, and Himachal Pradesh, and the region of Ladakh and Jammu and Kashmir, the reference date will be 1 October 2026.

It did not, however, specify when the survey would actually begin.

For the first time, the government will also collect the caste details - a politically and socially sensitive issue in India - of all its citizens, the statement added.

The last time caste was officially counted as part of a national census was in 1931, during British colonial rule.

India's census is conducted under the Census Act, 1948, which provides a legal framework for conducting the exercise, but does not specify a fixed schedule for when the census must be conducted or when its results must be published.

In 2020, India was set to begin the first phase of the census - in which housing data is collected - when the pandemic hit, following which the government postponed the exercise.

In the years since, the government further delayed the exercise several times without any explanation, even as life returned to normal.

Experts have spoken of the consequences this could have on the world's most populous country - such as people being excluded from welfare schemes, and the incorrect allocation of resources.

"The census is not simply a count of the number of people in a country. It provides invaluable data needed to make decisions at a micro level," Professor KP Kannan, a development economist, had told the BBC in 2023.