[{"_id":1,"title":"Item-001","tags":["red"]},{"_id":2,"title":"Item-002","tags":["red,yellow"]},{"_id":3,"title":"Item-002","tags":["redq,yellow"]},{"_id":4,"title":"Item-002","tags":[]},{"_id":5,"title":"Item-002"}]

db.collection.aggregate([{"$addFields":{"tagList":{$split:[{"$arrayElemAt":["$tags",0]},","]}}},{$match:{"tagList":"red"}}])