(4) Google Apps Script

gas.js

function myFunction() {
	var d = [
  {
    "city_name": "Oykot",
    "data": [
      {
        "capacity": 1000,
        "usage": 750,
      },
      {
        "capacity": 1200,
        "usage": 1000,
      },
      {
        "capacity": 800,
        "usage": 400,
      },
    ]
  },
  {
    "city_name": "Akaso",
    "data": [
      {
        "capacity": 1000,
        "usage": 790,
      },
    ]
  },
]
;
	var ss = SpreadsheetApp.getActiveSpreadsheet();
	for(i=0; i<d.length; i++){
		ss.insertSheet(d[i]["city_name"],i);
		for(j=0; j<d[i]["data"].length; j++){
			ss.setActiveCell("A"+(j+1)).setValue(d[i]["data"][j]["capacity"]);
			ss.setActiveCell("B"+(j+1)).setValue(d[i]["data"][j]["usage"]);
			ss.setActiveCell("C"+(j+1)).setValue(d[i]["data"][j]["usage"]/d[i]["data"][j]["capacity"]*100 + "%");
		}
	}
}