ymaps.ready(function () {
  var myMap = new ymaps.Map('map', {
    center: [53.902948, 27.557098],
    zoom: 9
  }, {}),
  objectManager = new ymaps.ObjectManager();
  myMap.geoObjects.add(objectManager);
  objectManager.add({"type":"FeatureCollection","features":[{"type":"Feature","id":101,"geometry":{"type":"Polygon","coordinates":[[/*...*/],[/*...*/]]},"options":{"fillColor":"#4861fb99","strokeColor":"#4861fbcc","strokeWidth":2}}]});
});

ymaps.ready(function () {
  var myMap = new ymaps.Map('map', {
    center: [53.902948, 27.557098],
    zoom: 9
  }, {});
  var newPolygon = new ymaps.Polygon([[/*...*/],[/*...*/]], {}, {
    fillColor:"#4861fb99",
    strokeColor:"#4861fbcc",
    strokeWidth:2
  });
  myMap.geoObjects.add(newPolygon);
});