Bar chart drill

I was trying to create a bar chart where i want to drill through district and then see the population of various cities for 3 year ranges. Basically i found this Drill down function for graphs embedded in Dash app - #9 by iTem but i am unable to implement

import dash
import dash_core_components as dcc
import dash_html_components as html
import plotly.graph_objs as go
from dash.dependencies import Output, Input, State
import numpy as np
import pandas as pd
import plotly.figure_factory as ff
from pandas import read_excel

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

# app = dash.Dash()
file_name = 'samplePop1.csv'
df = pd.read_csv(file_name)
print(df.head())

colors = {
    'black' : '#000000',
    'text' :  '#696969',
    'plot_color' : '#C0C0C0',
    'white' : '#FFFFF'
}


app.layout = html.Div ([
                        dcc.Graph(    
                            id = 'bar-chart',
                        figure = { 'data' : 
                                    [
                                        {'x' : df['Name'],'y':df['Population Census 1991'],'type':'bar','name':'Population Census 1991'},
                                        {'x' : df['Name'],'y':df['Population Census 2001'],'type':'bar','name':'Population Census 2001'},
                                        {'x' : df['Name'],'y':df['Population Census 2011'],'type':'bar','name':'Population Census 2011'}

                                    ],
                                'layout' : {
                                    'plot_bgcolor' : colors['white'],
                                    'paper_bgcolor' : colors['white'],
                                    'font' : {
                                        'color' : colors['white']
                                    },
                                    'title' : 'Bar Chart',
                                    'orientation':'h'
                                }
                                }
                        )
                    ])
if __name__ == '__main__':
    app.run_server(port =  '8080' , debug ='True')

the bar chart should show population district wise first for 3 year range and when i click on a district it shall show district wise comparison. also another basic chart where their will be 2 click action district wise and city wise to show population for 3 year ranges it should show values clearly more likely it should be scroll-able.

link to the csv file mapbox/samplePop1.csv at master · 9192gks/mapbox · GitHub

@9192gks any luck on this?