Street cleanliness in Basel is measured using a cleanliness index that ranges from 0 to 5, with values below 3 considered poor, between 3 and 4 moderate, and above 4 good. The Grand Council has set a target of achieving a city-wide cleanliness index of at least 4.5, which serves as the benchmark for evaluating whether street sections meet the required standard.

In September 2026, a total of 4,832 street sections were monitored, generating 122,431 individual measurements. The cleanliness index for that month ranged from a minimum of 3.69 to a maximum of 5.0, with an average value of 4.72. Overall, 87.7 percent of measurements exceeded the required threshold of 4.5, while 12.3 percent fell below it, indicating that the large majority of street sections met the target.

The top 5 and bottom 5 streets and districts in terms of cleanliness are presented in tables 1 and 2. Average cleanliness is only one possible metric for ranking districts, and rankings may differ when using alternative indicators, such as the percentage of measurements exceeding the 4.5 threshold. Therefore, a district with a high average index might still have a notable share of sections below the target, or vice versa.

Comparing the first available month, January 2024, with September 2026 shows a clear improvement over time. In January 2024, 67.8 percent of measurements exceeded the 4.5 threshold, and 98.8 percent were rated as good, meaning an index of 4.0 or better. By September 2026, these figures had risen to 87.7 percent and 99.8 percent respectively. This upward trend, illustrated in Figure 1, suggests that overall street cleanliness in Basel has improved substantially and is moving closer to consistently meeting the Grand Council's target.