Application.isLoadingLevel  

static var isLoadingLevel : boolean

Description

Is some level being loaded? (Read Only)

LoadLevel and LoadLevelAdditive don't happen immediately - a new level is loaded after the current game frame finishes. isLoadingLevel returns true if a level load was requested this frame already.

See Also: LoadLevel, LoadLevelAdditive.

print(Application.isLoadingLevel);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    void Example() {
        print(Application.isLoadingLevel);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    def Example():
        print(Application.isLoadingLevel)