According to Goal 7.2 of the Stadtentwicklungsplan Mobilität und Verkehr Berlin 2030 ("Urban development plan for mobility and traffic Berlin 2023"), the yearly average nitrogen dioxide (NO2) concentration should be below 30 µg/m³ in all Berlin streets ASAP (but definitely by 2030).

The relevant statistic can be downloaded as a XLSX file here: https://www.umweltbundesamt.de/staedte-no2-grenzwertueberschreitungen

This question will resolve as YES, iff the maximum value of all measurements of 2029 in the table from the Umweltbundesamt (downloadable above), for all rows concerning Berlin is below 30 µg/m³.

For reference: The current maximum value reported in the table is 37 µg/m³. Out of 26 measured values, 9 are currently at or above 30 µg/m³.