was falling, was becoming sick, was falling ill
A light snow was falling.
Une petite pluie fine tombait sur la ville endormie.
A light drizzle was falling on the sleeping city.
Dusk was falling.
L'huile me tombait dessus et le feu a tout brûlé.
The oil was raining down on me, and the fire burned everything.
— Le Tombeau des lucioles (1988)
On ne tombait pas malade, pas d’une maladie ordinaire, en tout cas.
You didn’t get sick—not with any ordinary illness, anyway.