This was reported by Reuters from statements made at a Parliamentary meeting in Beijing. Chen also indicated that a production line will be operating before the end of 2019. Previously, Elon Musk and Tesla have talked about completing a production line at the Shanghai Gigafactory by the end of 2019. Elon said the Shanghai factory is the biggest variable for [Tesla] to get to 500,000-plus a year. Tesla has $2 billion in loans at about 3.9% interest rate from Chinese banks to build and ramp the Shanghai Gigafactory. The completion of the factory could nearly halve the cost of Tesla Model 3 and Model Y electric cars into China. The current cost of a Tesla Model 3 RWD in China is ¥433,000 ($64,300). A base Model 3 built in a factory in China could cost $28,000 by avoiding tariffs and most taxes and because of 20% lower construction costs. The lower construction cost estimate was from Sandy Munro's estimate after a detailed teardown of Tesla Model 3s. There should be some near term tariff and tax relief from changes in China's VAT and tariffs. China will be stimulated its economy with a 3% reduction in its value-added tax. It seems likely there will be a China-US trade deal. The trade deal could happen by the end of March and will likely reduce US and China tariffs.
Building Tesla is a site that publishes satellite photos of the Shanghai Gigafactory. The latest photo is from Feb 23, 2019. Currently, satellite photos are not showing any major interesting site changes. There are various sources of regular videos posted of the construction. There is a lot of heavy truck, heavy equipment and pile drivers working at the site.