[Solved]-highcharts - avoid repeating same date on x axis with different time-Highcharts

You can put if condition with start date in label formatter function :

labels: {
    formatter: function () {
              if (this.value == Date.UTC(2010, 0, 1))
                return Highcharts.dateFormat('%d/%b/%Y %H:%M %p', this.value);      
              else 
                return Highcharts.dateFormat('%H:%M %p', this.value);
               }
 }

Check the updated jsFiddle