Database
[{"Name":"student1","marks":{"MP1":[70,80],"MP2":[60]}}]
Query
db.collection.aggregate([{"$addFields":{"marks":{"$map":{"input":{"$objectToArray":"$marks"},"as":"m","in":{k:"$$m.k",v:{"$filter":{"input":"$$m.v","as":"v","cond":{"$and":[{"$ne":["$$v",70]},{"$ne":["$$v",60]}]}}}}}}}},{"$addFields":{"marks":{"$arrayToObject":{"$filter":{"input":"$marks","as":"m","cond":{"$ne":["$$m.v",[]]}}}}}}])