Street cleanliness in Basel is measured using a computer system that analyzes video from street-sweeping vehicles to detect and count litter, producing a cleanliness index on a scale from 0 to 5. The Grand Council has set a target of achieving a city-wide cleanliness index of at least 4.5, which represents a high standard of public space maintenance.

In the most recent month, July 2026, a total of 4,942 street sections were monitored, generating 139,655 individual measurements. The average cleanliness index across all these measurements was 4.77, with values ranging from a minimum of 3.64 to a perfect maximum of 5.0. A strong majority of measurements, 91.5 percent, exceeded the required threshold of 4.5, while 8.5 percent fell below it.

The top five and bottom five streets and districts can be ranked by their average cleanliness index, though this is only one way to assess performance. Rankings may shift when using alternative indicators, such as the percentage of measurements that surpass the 4.5 threshold, and the full details are provided in the accompanying tables.

Comparing the first available month, January 2024, with July 2026 shows a clear improvement in street cleanliness over time. The percentage of measurements rated as good, meaning an index of 4.0 or better, rose from 98.8 percent to 99.9 percent. More notably, the share of measurements exceeding the strict 4.5 threshold increased substantially from 67.8 percent to 91.5 percent, indicating a strong and consistent upward trend.