environ vs aux environs de

Question

Why do we use "il a lieu environs de Mardi Gras" instead of just "il a lieu environ Mardi Gras"?

Céline Pickard · Accepted Answer

Bonjour Carl,
in French,  "environ + [quantity, number, duration...]" means "around/about/approximately + [quantity, number, duration...]" and is an adverb:
Il est environ quinze heures. = It is about 3pm.
Il y a environ 300 spectateurs. = There are about 300 spectators.
However, the prepositional phrase "aux environs de [quelque chose]" means "near/around [something]" and refers to the physical proximity to something or a point in time, which is what is used in the exercise:
Nous sommes aux environs de Paris. = We are close to Paris.
Il sera là aux environs de quinze heures. = He will be here around 3pm.
 
I hope this is helpful.
Bonne journée !