Complex sentence: Forbesganj, for a long time, was known for its jute production, but the advent of synthetic fibers, and mills closing down owing to non-profitability, made sure that the jute industry died a slow death.
Split into simpler sentences: Forbesganj, for a long time, was known for its jute production. But the advent of synthetic fibres, and mills closing down owing to non-profitability, made sure that jute industry died a slow death.