what do it mean? " are increasingly buing ...mass", "premium"

Question

The Chinese cosmetics and toiletries industry is the world’s eighth largest market for the industry and second largest of Asia. Increased disposable income has meant that more consumers can afford higher value products and so, are increasingly buying into the growing ‘upper mass’ sector or are trading up from mass brands to premium ones.

Answer 1

به طور فزاینده ای دارند بخش "طبقه بالای" در حال رشد را می خرند

premium = اعلاء