Economic progress for developing countries is surely an overall positive. However, for the tea industry in particular, the technical data seems to suggest that the effects are not all that good.
Economic progress and, subsequently, the inevitable urban development is beginning to encroach upon the historical tea estates of China and India, the two giants of tea production. Vast tea estates are now being surrounded by highways, condominiums and factories, causing a steady increase in undesirable elements entering into the tea production cycle. Here are some research papers that I have found that confirms our findings regarding the effects of urban development on tea production.
Since noticing this trend, I have done more digging to discover that the pollution problem is not exclusive to developing countries. Upon further research, it seems that all teas grown near or around any urban center face similar problems.
For all those buyers, distributors, wholesalers, retailers and, ultimately end consumers reading the postings on this site, I recommend that before you commit to a purchase, you may want to ask your vendor to show you documents of analysis or certificates of analysis (CoA). It may take a while, as the source documents may reside with the grower; however, I believe it is an important step of due-diligence that should be conducted to ensure that you are dealing and trading with the right kind of teas.