The fact that some people are blaming Nirmala Sitharaman instead of Arun Jaitley for slowdown shows that they know nothing about macroeconomics. While I myself don't like her as FM there is no way she is responsible for the GDP growth numbers.
The two main reasons behind the slowdown is the NBFC crisis which started after IL&FS went down due to fraud and the elections. The slowdown effect due to elections will go down as government starts spending and that will be seen in numbers for coming quarters.