News on environmental zones and air pollution

For years the annual average of nitrogen oxides has decreased from 81µg/m³ to 51 µg/m³ in Ludwigsburg (Baden-Württemberg)! Although it is always above the upper limit of 40µg/m³, diesel driving bans are not necessary, according to the authority. As part of the "Green City Master Plan", 30 million euros have already been provided by the federal government, the state and the district for new cycle paths, electric buses, etc. Will it take effect before 2020?