Hong Kong authorities have launched an investigation into the operator of four green minibus routes that have allegedly been overcharging passengers. Fully Mint Limited, which manages four minibus routes in the North District, had set fares between HK$0.30 and HK$1 higher than the approved amount, a government statement published on Saturday read. “We are following up on the matter seriously and have instructed the green minibus operator and relevant stored value facility operators to conduct thorough investigations and submit a report,” a Transport Department spokesperson said, according to l…