Error: Cannot find module 'gifsicle'

[rakeshshriwas]

root@empire-HP-250-G4-Notebook-PC:/var/www/html/Exploring# sudo gulp
module.js:540
throw err;
^

Error: Cannot find module 'gifsicle'
at Function.Module._resolveFilename (module.js:538:15)
at Function.Module._load (module.js:468:25)
at Module.require (module.js:587:17)
at require (internal/module.js:11:18)
at Object. (/var/www/html/Exploring/node_modules/imagemin/node_modules/imagemin-gifsicle/index.js:4:16)
at Module._compile (module.js:643:30)
at Object.Module._extensions..js (module.js:654:10)
at Module.load (module.js:556:32)
at tryModuleLoad (module.js:499:12)
at Function.Module._load (module.js:491:3)
at Module.require (module.js:587:17)
at require (internal/module.js:11:18)
at Object. (/var/www/html/Exploring/node_modules/imagemin/index.js:170:27)
at Module._compile (module.js:643:30)
at Object.Module._extensions..js (module.js:654:10)
at Module.load (module.js:556:32)
at tryModuleLoad (module.js:499:12)
at Function.Module._load (module.js:491:3)
at Module.require (module.js:587:17)
at require (internal/module.js:11:18)
at Object. (/var/www/html/Exploring/node_modules/gulp-imagemin/index.js:8:16)
at Module._compile (module.js:643:30)
at Object.Module._extensions..js (module.js:654:10)
at Module.load (module.js:556:32)
at tryModuleLoad (module.js:499:12)
at Function.Module._load (module.js:491:3)
at Module.require (module.js:587:17)
at require (internal/module.js:11:18)
at Object. (/var/www/html/Exploring/gulpfile.js:11:16)
at Module._compile (module.js:643:30)
at Object.Module._extensions..js (module.js:654:10)
at Module.load (module.js:556:32)
at tryModuleLoad (module.js:499:12)
at Function.Module._load (module.js:491:3)
at Module.require (module.js:587:17)
at require (internal/module.js:11:18)
at Liftoff.handleArguments (/usr/lib/node_modules/gulp/bin/gulp.js:116:3)
at Liftoff.execute (/usr/lib/node_modules/gulp/node_modules/liftoff/index.js:203:12)
at module.exports (/usr/lib/node_modules/gulp/node_modules/flagged-respawn/index.js:51:3)
at Liftoff. (/usr/lib/node_modules/gulp/node_modules/liftoff/index.js:195:5)
at /usr/lib/node_modules/gulp/node_modules/liftoff/index.js:165:9
at /usr/lib/node_modules/gulp/node_modules/v8flags/index.js:110:14
at /usr/lib/node_modules/gulp/node_modules/v8flags/index.js:38:12
at /usr/lib/node_modules/gulp/node_modules/v8flags/index.js:49:7
at _combinedTickCallback (internal/process/next_tick.js:131:7)
at process._tickCallback (internal/process/next_tick.js:180:9)
at Function.Module.runMain (module.js:686:11)
at startup (bootstrap_node.js:187:16)
at bootstrap_node.js:608:3