évolution de la pollution

CONT: Sur les figures 1 à 4, on a placé en ordonnée la pollution brute (exprimée en poids ou en équivalents-habitants) et le temps en abscisse : la droite x = at + b retrace la prévision de l'évolution de la pollution.

CONT: As part of economic planning, and in line with planning goals, the Agences de bassin prepare pluri-annual action programmes describing the steps which must be taken for developing water resources and for controlling pollution. (...) It should be noted that these are based on pollution trends and needed action over a long period (20 years).