People before they are living in the countryside with forests. The mountain streams or at least to have air pollution thus making them stronger, healthier people in the present.
Initially they were to live in the countryside with forests, mountains or streams. Much less to air pollution. As a result, they are in good health. Stronger than currently
Old people, they live in the countryside with forest, mountain, or a little brook to polluted the air. So they have good health, stronger than the present.