Read the scenario and answer the following questions: Please provide explanation and a graph for each part

Electric cars are sometimes advertised as "zero emission vehicles." It's a label popular with marketers and even some government regulators that are trying to clean up city airsheds and reduce pollution. The only problem is that electric cars generate plenty of emissions - just not where they're driving around. When an electric car is charging overnight, it is drawing on a regional power grid and prompting power plants across the network to produce slightly more electricity, the emissions at those power plants could be pretty dirty in their own right.

Q1a. Identify and explain using a graph what type of externality arises due to the emissions from the electric cars?

Q1b. What measure should the government take to reduce the emission ?

(Hint: Support your answer with appropriate graphs)