Digging deeper into the data, we can try and understand why public bus services in certain cities (such as Delhi) are so much more expensive to operate than those in other cities (such as Bengaluru or Chennai).

The problem with Delhi is that not only does it have a higher cost of operations compared with other cities and states, but its utilization (both in terms of fleet and passenger kilometres carried per bus) is also much poorer. These two factors help explain why Delhi’s bus system costs six times as much as Chennai’s in terms of cost per passenger kilometre.

While there are several costs associated with running a public bus system (capital costs, salaries, fuel, maintenance), it is not unreasonable to assume that the cost is directly proportional to the size of the fleet. The data (published by the roads ministry in the 2015 Statistical Yearbook by the statistics and programme implementation ministry) confirms this hypothesis.