Just came across the attached article which presents results from a survey in the city of Dehradun (India).
Some interesting highlights:
- Vendors need light 2.5 hours per day in summer and 3.45 hours per day in winter.
- Of the current vendors, 59% use pressurized kerosene lanterns, and 21% rely on streetlighting.
- Daily expenditure for kerosene is 13.4 Rs (or about $0.21).
- There was high preference for a solar lantern rental option (over direct purchase).