Complex sentence: Sales of new energy vehicles since 2011 passed the 500,000 unit milestone in March 2016, while sales of new energy passenger cars achieved the 500,000 unit milestone in September 2016, both, excluding imports.
Split into simpler sentences: Sales of new energy vehicles since 2011 passed the 500,000 unit milestone in March 2016. Cumulative sales of new energy passenger cars achieved the 500,000 unit milestone in September 2016, excluding imports.