Please can any one tell me what is false base line???

Usually, when we draw any graph, the scale on which the graph is measured starts from zero on the y-axis. However, under the situations when the data to be plotted on graph starts from a value which is far above zero, results in the problem of shortage of space on graph. To overcome this problem of shortage of space, a false base line is plotted. False base line is a line which is drawn to grasp the attention of the reader on the fluctuations which usually remains unnoticed. 

 To understand it better, let's take an example relating to the per capita income of any particular country during some decennial periods.  

In the above figure, the dotted line starting from 30 represents False Base Line.