getImgJson: error: unable to get local issuer certificate

Hi:
When using 
PS C:\Users\ramakrishnan.s\Desktop\Sample projects\node-docker-registry-client> node examples/v1/getImgJson.js mongo:latest

Getting error as getImgJson: error: unable to get local issuer certificate ..
Hwo to fix it ? Pls help .. Thanks in advance..

Same thing happens for ping.js too..

Ramki