Let me say this bluntly: China practices atrocious environmental responsibility, and the Communist government in charge there cares nothing about mass use of pesticides, industrial pollution, or the safety of the food supply. Some of the most toxic food products in the world are found in China. I know, I've been there and I've seen it first hand.
This is why you should consider sourcing your green tea from somewhere other than China. Get it from an organic source, some place that doesn't spray it with pesticides. It's more expensive, of course, but it's also safer for your health.
Green tea is a nutritional supplement with phenomenal health-enhancing properties. It boosts healthy body function in so many ways that it's hard to imagine any person who wouldn't benefit from taking some. But if your green tea is contaminated with pesticides or other substances (such as fluoride, another toxic chemical frequently found in green tea), you may be doing more harm to your health than good. So always check the sources of the foods and nutritional supplements you purchase. And don't trust food products or nutritional supplements from China. Until the nation cleans up its act, it's probably the most highly contaminated place in the world for producing foods. (Even the Chinese largely agree with this, by the way. It's just a fact of life in China.)