revision preference src: Bhutanese opponents argue that allowing foreign vehicles within the country would pollute its natural environment. In 2018, it was reported that Bangladesh, India and Nepal could move forward with implementation without Bhutan. <SEP> tgt: Bhutanese opponents argue that allowing foreign vehicles within the country would pollute its natural environment. In 2018, it was reported that Bangladesh, India and Nepal could move forward with implementation without Bhutanese.