Translate the following English sentence to French:
"There should be no falling-off in the percentages concerned or in the requirements for recycling vehicles from particular years, and it is important to limit the use of dangerous substances such as lead."
Les pourcentages et les exigences relatives au recyclage à certaines dates ne doivent pas perdre de leur force et il est important de limiter l'utilisation de substances dangereuses telles que le plomb.