Hi Gibran, Thanks for the feedback. The bad odor is because of the SILICA GEL PACKET that's inside the bottle, and goes away after the first wash and usage.
Silica gel is used to dry the air in industrial compressed air systems. Air from the compressor discharge flows through a bed of silica gel beads. The silica gel adsorbs moisture from the air, preventing damage at the point of use of the compressed air due to condensation or moisture.
Thanks and hope this helped.