Remove specifc pin from map Google Maps xcode - ios

Question

I have an array which stores data from webservice. The data contains multiple locations.
The array updates when the map center is moved. It shows pins based on map center. What i want to do is to remove those old pins that i have allotted on the map without removing all the markers and if new pins are stored, allot them without adding all of them again.
Thanks in advance.
Here is my code.
if ([tempOLDArr count]>0) {
for (int i = 0; i<[appdelegate.eventsArray count]; i++) {
eventsWebService *temp = [appdelegate.eventsArray objectAtIndex:i];
if (i<[tempOLDArr count]) {
if ([temp.eventID isEqualToString:[[tempOLDArr objectAtIndex:i]eventID]]) {
}
else {
[tempNEWArr addObject:[appdelegate.eventsArray objectAtIndex:i] ];
}
}
else if(i>=[tempOLDArr count]){
[tempNEWArr addObject:[appdelegate.eventsArray objectAtIndex:i] ];
}
}
if ([tempNEWArr count]>0) {
[self creatingAnnotation:tempNEWArr];
}
}
else {
tempOLDArr = appdelegate.eventsArray;
[self creatingAnnotation:tempOLDArr];
}
And here is my code for plotting those markers
-(void)creatingAnnotation:(NSArray *) eventsArr{
for(int i=0;i<[eventsArr count];i++)
{
HomeEventLat = [[appdelegate.eventsArray objectAtIndex:i]eventLat];
HomeEventlong = [[appdelegate.eventsArray objectAtIndex:i]eventLong];
double pickuplat = [HomeEventLat doubleValue];
double pickuplng = [HomeEventlong doubleValue];
CLLocation * loca=[[CLLocation alloc]initWithLatitude:pickuplat longitude:pickuplng];
CLLocationCoordinate2D coordi=loca.coordinate;
eventMarker = [[CustomGoogleMarker alloc]init];
eventMarker.position = CLLocationCoordinate2DMake(pickuplat, pickuplng);
eventMarker = [CustomGoogleMarker markerWithPosition:coordi];
eventMarker.snippet = NO;
eventMarker.icon = [UIImage imageNamed:#"map-pin-icon"];
eventMarker.tappable = YES;
eventMarker.marker_description = [[appdelegate.eventsArray objectAtIndex:i]eventDetail];
eventMarker.marker_distance = [[appdelegate.eventsArray objectAtIndex:i]eventdistance];
eventMarker.markerID = [[appdelegate.eventsArray objectAtIndex:i]eventID];
eventMarker.marker_joinedNo = [[appdelegate.eventsArray objectAtIndex:i]eventJoinedNo];
eventMarker.marker_price = [[appdelegate.eventsArray objectAtIndex:i]eventPrice];
eventMarker.marker_commentsNo = [[appdelegate.eventsArray objectAtIndex:i]eventCommentsNo];
eventMarker.marker_address = [[appdelegate.eventsArray objectAtIndex:i]eventAddress];
eventMarker.ID = [NSString stringWithFormat:#"%d",i];
// eventMarker.appearAnimation = kGMSMarkerAnimationPop;
NSString *markerLabels = [[appdelegate.eventsArray objectAtIndex:i]labelsList];
NSLog(#"%#",markerLabels);
eventMarker.marker_label = markerLabels;
eventMarker.marker_username = [[appdelegate.eventsArray objectAtIndex:i]user];
eventMarker.marker_time = [[appdelegate.eventsArray objectAtIndex:i]eventTime];
eventMarker.marker_image = [[appdelegate.eventsArray objectAtIndex:i]eventimage];
// eventMarker.title = [[appdelegate.eventsArray objectAtIndex:i]eventsID];
//
// [self.mapView clear];
eventMarker.map = self.mapView;
//
//
[markerDetail addObject:[appdelegate.eventsArray objectAtIndex:i]];
}
[_mapView animateWithCameraUpdate:[GMSCameraUpdate fitBounds:bounds withPadding:10]];
}