[Chartjs]-Apply color only to lower part of Chart.js line chart

my solution –

    datasets: [
        {
          fill:'start',
          backgroundColor: 'what you want',
          ...
        }

http://www.chartjs.org/docs/latest/charts/area.html

Looks like your chart is filling to the origin, since you have negative and positive data this makes it fill above and below 0. Try adding:

fill: 1,

This should fill to dataset 1 and fill in the data you have.