scanning and georeferencing 6,598 physical maps: 35 maps of states and union territories, 640 district maps, and 5,923 subdistrict maps.

The subdistrict maps present the administrative boundaries of towns and villages in their jurisdiction. The location, size, and shape of these towns and villages were digitized in the form of 649,818 boundary polygons. Attributions such as location codes, names, and administrative types were added to the polygons. This study takes advantage of these attributions. Information on the administrative types of the cities, towns and villages allows a refined stratification strategy for sampling.

Data on administrative boundaries are adjusted for this study in three ways. First, in the original database multiple polygons were retained for towns that extended over more than one subdistrict. In this study, those multiple polygons are merged into a single administrative boundary for each town. This results in 649,649 units whose boundaries have a one‐to‐one correspondence with administrative units.

Second, some villages were presented as points on the source maps and their boundaries were  unavailable, totally or partially they are mostly in the mountainous or forest areas of four states (Arunachal Pradesh, Chhattisgarh, Himachal Pradesh, and Meghalaya). These villages are excluded from the analysis. And, third, population information was not available in the 2011 Census of India for some villages, which raises concerns about the quality of the corresponding official maps. These villages are excluded as well.

As a result of these mergers and exclusions, 564,052 administrative units with well‐identified boundary polygons are retained as the universe for the analysis. However, for the purpose of extracting a sample of cities, towns and villages, the set of administrative units is further restricted to those belonging to the 21 largest states and union territories. These large states and union territories are covered by the high‐quality household surveys whose data are needed for a proper stratification. Focusing exclusively on them further reduces the number of administrative units considered to 561,624.

The total population of these 561,624 polygons in 2011 was 1,174 million, or 3.0 percent less than reported by the 2011 Census for the country as a whole (ORGI 2011). Almost a third of this population gapabout 11.3 million peopleis accounted for by the small states and union territories excluded from the analysis. Some of these small states and union territories are richer than the Indian average and some are poorer, which suggests that their exclusion from the analysis may not bias results much. The rest of the gap is associated with the villages excluded because their boundaries or population figures were unavailable. These villages are most likely rural in practice, and their population size is small about 200  people at the median which implies that they too are unlikely to be an important source of bias.

# _A two‐stage stratification process_

A two‐stage disproportionate stratification approach is used to select the sample of administrative units to be inspected visually (figure 1). In the first stage, the universe is divided into eight strata by administrative category, following the definitions of the 2011 Census of India. Five of these categories state capitals, other municipal corporations, municipalities, industrial towns, and other townsare statutorily designated as urban. All state capitals are governed as municipal corporations; we use the term other municipal corporations to refer to the rest of the cities in this administrative category. Two of the   categories census towns and outgrowths are statutorily rural but recognized by the 2011 Census as 5