6. According to the article "Bets on electric vehicles light up lithium miners and battery makers": Wang said the lithium market faced the risks of supply lagging behind demand over the next couple of years because of new mining projects could face delays. That could limit carmakers' ability their ambitious targets for EVs, he said. "It looks like it [the market] might be balanced - but if it's balanced, it will be a very tight balance", he said. What is the situation of the lithium market? What does it mean "a very tight balance?"